The bigger a vendor, the more likely you are to find they have multiple personalities. Different products are sold, developed and maintained by different divisions of the company, which are often groups that were assimilated through acquisition. OpenText and Adobe are the two suppliers I've seen demo different products in their marketing or customer experience suites, and every time, it's like watching a different vendor.
As a buyer, it's important to understand the origins and technical roots of any product you're buying, and also, the culture of the assimilated company — in one sense you'll be acquiring that, too. I've seen for example a massive difference in how Adobe presents themselves and the levels of knowledge of the teams that sell Adobe Campaign vs. AEM-Assets. It quickly becomes clear that Adobe acquired an experienced email marketing campaign team with Neolane, but did not acquire a deeply experienced DAM team or product with Day's CQ — rather, they acquired a WCM and have bolted on DAM components since then.
We can come back to the best-of-breed vs. "suite" argument here, and this is a case in point of why suites aren't always sweet. You may get a highly mature, fit-for-purpose tool for certain types of campaign management, but you might not get the most appropriate DAM if you buy both from the same vendor.
As always: know the potential pitfalls. RSG's Digital Marketing research identifies the strengths and weaknesses of key tools within the major suites.