Amapi is ecclectic. I have version 6 and will say that I found something oddly intuitive about the interface - once I got into the workshop metaphore on which it's based. Funny thing is, I went back to it a couple of weeks ago and found that, after learning Hexagon, I could get quite a lot out of it. The documentation is Amapi's worst enemy. I uninstalled it again after that, after all, its redundant to me now - although it does support NURBs but they just don't interest me right now.