Definitely have a Floyd-lite vibe. I love the earlier stuff like Tales, I Robot, and Turn of a Friendly Card, but much of their 80s output is kinda bland. Alan Parsons solo (still sounds like APP, but without Wolfson) is pretty decent too, and David Gilmour plays a guitar solo (as well as the Keep Talking riff) on 2004's "Return to Tunguska."
I was dissapointed when I first found out that Parsons turned down the engineering job for WYWH, but after ToMaI, I can't say he made a bad decision. APP didn't really churn out a bad album. It stopped officially on a strong note (Gaudi) and all the albums are very memorable.
My personal favourites are Tales of Mystery, Eye in the Sky and Ammonia Avenue with Gaudi and I Robot not far behind.
Supertramp's first album has a early 70s Floyd vibe (and sounds very little like later poppier Supertramp, although I love those albums too)