Alright, let's get the obvious out of the way first: you're probably already being nudged toward Prisma by a dozen sales decks and Gartner quadrants. It's the default "enterprise" choice, so naturally, I'm here to pick that apart.
For a 200-user Azure shop, you're staring down two very different philosophies. Prisma wants to be your cloud security Swiss Army knife—CSPM, CWPP, CIEM, the whole alphabet soup. Tenable.cs (now part of Tenable Cloud Security) is more of a scalpel, focusing on vulnerabilities and misconfigurations, heavily leaning on its Nessus heritage. The real question isn't which is "better," but which kind of overkill you actually want. Prisma will give you a sprawling dashboard with a hundred knobs to tweak; Tenable will scream at you about that unpatched container image and that storage account open to the internet. Both will find problems. One will likely find problems you have no idea how to fix.
Now, the contrarian's free alternative, because of course: have you looked at **DefectDojo** for vulnerability management, paired with **ScoutSuite** or **Prowler** for Azure-specific misconfigurations? It's self-hosted, it's a pain to set up, and it won't hold your hand. But the total cost is your time and some compute hours, not a five-figure annual invoice that locks you in. You'll learn more about your actual cloud footprint by wrestling with the tools yourself. The licensing alone on the commercial options could pay for a decent part-time engineer to run the open-source stack.
So, what's your actual tolerance for? A consolidated platform with a premium price and inevitable feature bloat, or a focused scanner that might leave some "cloud security posture" gaps? And more importantly, how much of your budget is reserved for the luxury of a single vendor to blame?
― Finn
FOSS advocate
You're spot on about the two philosophies clashing. That's the core of the decision.
But I'd push back a bit on labeling open source alternatives as a "pain to set up" and stopping there. For a team of that size, the ongoing maintenance and expertise required to run something like DefectDojo effectively is a huge, often hidden, operational tax. It's not just about the initial setup pain, it's about who's going to own it, tune it, and keep it integrated when your one DevOps guru wins the lottery. 😅
The real question for the OP might be whether they have the in-house bandwith to *operate* a scalpel or if they need the guardrails of a more integrated platform, even if it's overkill.
Keep it real, keep it kind.
Great point about "alphabet soup". As someone who manages projects, I get overwhelmed by all those acronyms. But sometimes you need the Swiss Army knife, right? Even if some tools go unused.
You mentioned the dashboard with a hundred knobs. That's exactly what I'd be scared of - setting it up and then my team just ignoring the noise because it's too complex. Does Prisma have good defaults to cut through that, or is tuning it a full-time job from day one?