Yeah, when I first switched from UBB -> threads it was still 5.5, and my users were about 50/50. Some loved the new features, others were like "its too hard to follow, I'm not good at computers". Others were just overwhelmed by all the options, like flat or threaded mode, etc. But once I posted instructions and what each feature does people really got used to it.
Now, everyone loves it, compliments on how fast it is, all the features, etc. I think they would all drag me out into the street and shoot me if I ever changed software again

Like Allen said, I think once most of the features are in the program and running well more time will be spent focusing on enhancements to the gui to make it as userfriendly as possible. The small buttons replacing text links (or at least an option to do that) is just one of the many ways to do that.
