Ok, I do remember jamstix. It looks to me like BFD3 (and BFD2) does a lot of the things jamstix does but just in a different way though I have to say jamstix does look like it has some useful features.
When you said engine you meant midi engine I'm guessing.
I never use loops in my own songs so jamstix isn't really for me but it looks a useful tool.
There are a lot of things regarding realism BFD3 can do that jamstix can't do, at least at first glance but I have to say after watching the jamstix 3 video it looks excellent for song creation. I had a demo of jamstix one years ago but didn't have much use for it.
Maybe I'll give it another go.
Steve