With Forrester's publication of their SOA Management Wave (which I believe you will be able to download from the Actional website if you're interested) it's clear that the two largest analyst firms covering the SOA space disagree on SOA Management.
Forrester's view is that SOA Management is a distinct product category from SOA Governance. Gartner, on the other hand, believe SOA Management is a part of the SOA Governance product category. Having seen it all behind the scene's, it's actually pretty funny (in a pathetic kind of way) -- the vendors that think they would do better by having it combined have lobbied Forrester to change their model, and others have lobbied Gartner to change theirs.
So, which one is right? In some ways they are both right -- it's just a matter of where they put the emphasis. First, though, SOA Management is clearly a distinct technical competency from the rest of SOA Governance. Most SOA Governance products tends to focus most on controlling the behavior of people -- e.g. what they are allowed to do and when. In contrast SOA Management focuses most on controlling the behavior of applications and services -- e.g. how are they performing and are they secure.
But, the views of Gartner vs. Forrester actually come down to a pretty simple question: Where do you set your priorities?
If your priority is "I'd rather have products that do their job well and provide good integrations with products in the other areas," then you take the Forrester view and should probably listen to what they have to say.
If your priority is "I value a single integrated solution more than having good capability in any functional area," then you probably take the Gartner view of the world and listen to what they have to say (Gartner has historically always pushed "stacks" -- so it's no surprise they do the same here).
Of course, in the end, it's not so simple. In marketing land, a vendor's products are all above average and integrate well with all the other products in its portfolio. But, in the real world it's often a bit different... I can't speak for other markets, but in this market any vendor that has built a "complete stack" themselves is significantly functionally deficient in one area or another. On the other hand, the ones that have licensed portions of their stack have only average (at best) integrations.
Given there is no perfect answer - no magic bullet - what should you do? In the end, I can't answer that for you either, other than offering the following two pieces of advice:
- Do an analysis of the products (functionally, architecturally, and how they integrate with other products). This will serve as the groundwork for prioritizing what's important to you no matter what path you take. Remember, it's not black-or-white (don't choose a stack just because the vendor has one because you might get stuck with a costly mistake).
- Be careful of selecting an application platform vendor as your management or governance vendor. They typically only support their own application platform well (and the others are checklist items... at best). If theirs is the only SOA infrastructure you have (or will ever have), then perhaps that's a good choice -- but otherwise you're leaving the fox to guard the henhouse. With both management and governance it's critical to choose a solution that's application platform vendor agnostic.