I watched Dune 2.
It was good. First half was a lot like Avatar which was funny. Liked it better than the first.
I remember when I was in university, I took a Science Fiction course (English class). Dune was one of the books we needed to read. Our prof said "Just watch the mini-series, it's close enough". So I "found it" on Kazaa since Space showed it randomly. I rememeber having a conversation with my class mates in one of the labs about how Frank Hurbert's son had found his (Frank's) notes, so he was going to write out the ending.
Anyways, I saw Dune 2 over the summer on T.V. and it was more or less a scene by scene of the mini-series, just with movie budget. So I'll assume it was pretty close.