A lot of SI's are married to a particular software platform, and it's been that way for a long time. We all know the big player who owns 70-80% of the market, and most people will implement via them (or that's at least what they make most of their money off of).

Some of us (I work for an SI) actually find the correct solution for the problem. We use all 4 major players, build our own stuff when appropriate, and would look at other solutions if the opportunity arrises, we love what we do.

Let me know if you're still looking for a solution and I'd be happy to give you another opinion.