We have used this to integrate, Magneto, Moodle and Elgg while everything didn't go flawlessly it did work out in the end, most of the issues we experienced we due in part to our lack of understanding. But for what it does I really don't think there is anything better at bridging the gap to integrate other frameworks that Jfusion.
There support is also fairly good. I had one issue with a micro integration and they fixed it for me. Granted the total turn around time on the fix wasn't the fastest I've seen but none the less they didn't ignore me like some companies.
So in my book they are A. OK :)