I don't think you could consider Gilmour in any way under rated. He's viewed in the guitar world/community as a living 'tone God'. I was watching Classic Albums lastnight on VH1 and it was covering 'The Dark Side of the Moon' and Gilmour's playing and writing was just amazing to behold. He's one of those players that can get more from one note than most guitar players get on an entire song.
As for sloppy, it can be worked into an incredible style as well. SRV was probably the king of sloppy but he controlled it into an amazing technique that's extremely hard to copy.