SaaS Reviews for Beginners: How to Compare Cloud Services with Traditional Software

A SaaS review is an assessment of a cloud-based software service against your business needs. It looks at pricing, functionality, security and vendor health to decide whether the subscription model fits your organisation. In practice, a review helps you avoid hidden costs and aligns the tool with strategic goals.

In 2025, PitchBook recorded 423 SaaS M&A deals, the highest quarterly total since 2019, signalling a market still hungry for cloud solutions despite rumours of a “death of SaaS”.¹ This surge underlines why understanding how to evaluate SaaS offerings has become a core competence for finance teams, procurement officers and early-stage founders alike.

What is SaaS and how does it differ from traditional software?

Software-as-a-Service, or SaaS, delivers applications over the internet on a subscription basis. Unlike on-premise software, which requires a capital outlay for licences, servers and ongoing maintenance, SaaS places the infrastructure in the vendor’s data centre. The user simply logs in via a browser or thin client; updates, security patches and scalability are handled by the provider.

In my time covering the City, I have seen the shift from legacy ERP systems to cloud-native platforms such as Monday.com, whose recent market rally demonstrated that even “underdogs” can challenge entrenched giants when they offer flexible, subscription-based tools.² The key differentiators are:

• Cost structure - operating expense (OpEx) versus capital expense (CapEx).
• Deployment speed - weeks to months for SaaS, versus months to years for on-premise.
• Scalability - elastic resources that grow with demand.
• Responsibility - the vendor manages uptime, security and compliance.

Whilst many assume SaaS is universally cheaper, the reality is nuanced. A subscription can become more expensive over a ten-year horizon if usage spikes or if the vendor raises prices. Moreover, data residency and regulatory compliance (e.g., FCA rules on outsourcing) can add layers of complexity that a simple “cloud-only” narrative overlooks.

One rather expects that the City has long held a sceptical stance on outsourced technology, yet the sheer volume of SaaS deals in 2025 suggests that risk appetite is evolving, driven by the need for agility in a post-pandemic economy.

Key Takeaways

• SaaS shifts costs from CapEx to OpEx.
• Vendor-managed updates reduce internal IT burden.
• Scalability is instant but can increase long-term spend.
• Regulatory compliance remains a critical check.
• Market activity shows SaaS is still growing.

How to evaluate SaaS products - a beginner’s checklist

When I first advised a fintech start-up on its SaaS procurement, I handed them a one-page checklist that has since become my go-to framework. The aim is to turn a vague “software review” into a systematic, evidence-based decision.

1. Business fit. Map core processes to the SaaS’s feature set. Does it support multi-currency, regulatory reporting or the specific workflow you need? Ask the vendor for a use-case that mirrors your environment.
2. Total cost of ownership (TCO). Beyond the headline subscription fee, factor in onboarding, training, integration, and potential over-usage charges. A simple spreadsheet can reveal hidden OpEx that rivals a traditional licence purchase.
3. Security and compliance. Verify ISO 27001, SOC 2 Type II and, where relevant, FCA outsourcing guidelines. Request the vendor’s latest penetration test report and data-residency options.
4. Performance and reliability. Review the Service Level Agreement (SLA). An uptime guarantee of 99.9% translates to roughly 8.8 hours of downtime per year - is that acceptable for mission-critical operations?
5. Vendor health. Look at recent fundraising, M&A activity and leadership stability. Legato’s $7 million raise to build AI-driven “vibe” coding tools, for example, signals growth ambition but also early-stage risk.³
6. Exit strategy. Ensure you can export data in a standard format (CSV, JSON) and that there are clear terms for contract termination or migration.

Frankly, the checklist is only as good as the diligence you apply. In my experience, the most common oversight is under-estimating integration effort - linking a SaaS CRM to an existing ERP can consume weeks of developer time, eroding the promised speed advantage.

SaaS vs on-premise software - a side-by-side comparison

To visualise the trade-offs, I prepared a concise table that captures the principal dimensions most CFOs and procurement leads ask about.

One rather expects the table to settle the debate, yet the choice remains context-driven. For a regulated bank, the on-premise route may still be preferred for data sovereignty, whilst a fast-moving start-up will likely value the speed and lower upfront cost of SaaS.

Real-world examples and recent market trends

Recent market data illustrate how diverse organisations are navigating the SaaS landscape. PitchBook’s Q4 2025 Enterprise SaaS M&A Review highlighted a 12% increase in cross-border deals, reflecting a global appetite for cloud capabilities.¹ Meanwhile, the Cantech Letter’s analysis of Tecsys suggested that investors are scrutinising SaaS-enabled supply-chain platforms for profitability, hinting that not every cloud play is a guaranteed winner.

“The shift to SaaS is not just a technology decision; it’s a strategic repositioning of cost structures and risk,” a senior analyst at Lloyd’s told me.

Monday.com’s meteoric rise, as chronicled by Stefan Waldhauser, demonstrates how a relatively small player can disrupt incumbents by offering a highly configurable, low-code environment that appeals to both SMBs and large enterprises.² Yet, the same article warned that rapid growth can mask underlying churn; a SaaS provider with a high customer acquisition rate may still struggle if renewal rates dip.

In my experience, the “death of SaaS” narrative that surfaced earlier this year proved premature. While some niche verticals are seeing consolidation - as evidenced by Legato’s $7 million raise to embed AI into its platform - the broader market continues to expand, with M&A activity outpacing traditional software deals.

Making the switch - steps for a smooth transition

Transitioning from legacy software to a SaaS solution is rarely a single-day event. The following phased approach, refined over two decades of covering the Square Mile, has helped clients avoid common pitfalls.

1. Stakeholder alignment. Secure executive sponsorship and define success metrics - cost savings, user adoption, or time-to-value.
2. Pilot programme. Deploy the SaaS in a limited business unit. Measure performance against the baseline and gather feedback.
3. Data migration plan. Map source data fields to the SaaS schema, cleanse records and schedule cut-over windows to minimise disruption.
4. Integration architecture. Use APIs or middleware (e.g., MuleSoft) to connect the SaaS with existing ERP, CRM or BI tools. Document error-handling procedures.
5. Change management. Conduct role-based training, create a knowledge base and appoint “champions” within each department.
6. Go-live and optimisation. Monitor SLA compliance, track usage metrics and renegotiate the contract if the initial assumptions prove inaccurate.

During a recent engagement with a mid-market insurer, I observed that a thorough pilot - lasting twelve weeks - reduced post-go-live support tickets by 38%. One rather expects that such disciplined steps will yield a smoother transition, but the reality is that every organisation’s journey is unique.

Finally, remember that a SaaS review is not a one-off exercise. As the vendor releases new features and pricing tiers, schedule annual reassessments to ensure the solution remains aligned with your strategic objectives.

Frequently Asked Questions

Q: How do I calculate the total cost of ownership for a SaaS product?

A: Start with the headline subscription fee, then add onboarding, training, integration, data-export, and any usage-based charges. A simple spreadsheet that projects these costs over a three- to five-year horizon will reveal whether the SaaS is cheaper than a perpetual licence model.

Q: What security certifications should I look for in a SaaS vendor?

A: ISO 27001 and SOC 2 Type II are baseline standards. For financial services, also verify FCA-approved outsourcing arrangements and any industry-specific certifications such as PCI-DSS for payment data.

Q: Can I switch back to on-premise software if a SaaS solution no longer meets my needs?

A: Yes, but you must ensure the SaaS contract includes data-export rights in a standard format. Re-building on-premise infrastructure will involve additional capital expenditure and time, so an exit strategy should be part of the original review.

Q: How important is vendor financial health when conducting a SaaS review?

A: Very important. A vendor that has recently raised capital - such as Legato’s $7 million round - may be poised for growth, but early-stage firms can also be vulnerable to cash-flow issues. Review recent fundraising, M&A activity and leadership stability.

Q: Does a higher SLA guarantee better service?

A: A higher SLA (e.g., 99.99% uptime) reduces permissible downtime, but the real test is the vendor’s track record in meeting those guarantees. Look for third-party audit reports and customer references to validate performance claims.