If you've been looking at tools at all, you've doubtless noticed that vendors (and many consultancies, and some analyst firms) tend to take something other than a scenario-based approach. Some use horserace concepts to distinguish solutions, trying to answer the ubiquitous question, "who's leading?" You should, in turn, ask, "leading at what?" That fact is that different scenarios favor different products.
Other vendors and commentators look at size. Large vendors with complex platforms claim that their smaller competitors can't scale, saying in effect, "Don't send a boy to do a man's job." Lower-tier players retort, "Don't kill a fly with a cannon." Yes, size and extensibility matter, but from a business perspective, you risk losing the more important point around "fit" here.
You want to find a good fit with your business objectives. First that means figuring out which type of technology will provide the biggest near-term value. Then it means knowing what type of scenario(s) you're addressing, to begin to isolate vendors that potentially hit that sweet spot. It doesn't matter whether you employ the list of scenarios above or not; the key goal is to carefully outline what you're trying to achieve with which types of content. A little analysis up front before you commit to the wrong technology path can save you a lot of time and money later.