I've just finished a relatively painless install, and am quite impressed with the guided install. A few comments:
[-] It would be good to say exactly what number (755, 664, or whatnot) is needed to make the docs, etc., files writeable. I finally had to set them to 777, which I don't think is exactly correct.
[-] While I can read the font just fine, one or two pixels bigger would be much nicer.
[+] I really love the new look of the admin panel. The frames in phpBB2 were extremely annoying.
[-] In the forum creation panel, the line under "Forum Description" that reads, "Any markup entered here will displayed as is" is a little confusing, especially when there are the checkboxes underneath saying "Parse BBcode" and so on. And what difference is there between "parse links" and "parse BBcode"? Doesn't BBcode have the [url] tag?
More to come.... and should these be in another forum?