I don't find Steve Vai's music boring at all, I am actually amazed at how many different sounds and directions Vai takes in some cases within a singal song.
As far band situation, I would say his best band was with David Lee Roth, but I also loved the work he did with Frank Zappa. Alcatrazz was ok, but I didn't feel the songwriting was that strong on the album he recorded with them. Whitesnake was ok, but it sounds like he was added on at the last minute, which in fact he was.
The Public Image LTD album he appears on titled "Album/Compact Disc/Cassette" (depending on the format you bought on) is stunning.