I get many questions from clients interested in evaluating different in-memory technologies. My first advice is not to mix apples and oranges and clearly understand the differences between in-memory indexes, in-memory OLAP, in-memory ROLAP, in-memory spreadsheets, and other approaches. See more details in my recent blog entry "I forget: what's in-memory?" to understand the differences. Then once you zero in on a particular segment, you can indeed do an apples-to-apples comparison. Let's say we pick the category of in-memory associative indexes, which would include Microsoft PowerPivot, QlikTech, and TIBCO Spotfire. We also sometimes run across Advizor Solutions, but typically in smaller clients (and we do not include them in The Forrester Wave™ process). I recommend a three-step approach to compare these four tools:
First, compare all of the commodity features of the vendors and tools like data integration and portal integration, operational features like administration, security, and others. You can leverage the detailed evaluation behind our slightly outdated 2008 BI Forrester Wave, if you are in a hurry, or you can wait for another month or so and the 2010 update will be published (it's in the last stages of editing at this point). Or if you are a Forrester IT client — not a vendor — client, send me a note and I'll share a draft preview with you.