I’ve used a ton of DAWs, on Windows (98, 2000, XP, and 7), OS X, and iOS.
Windows: Cool Edit Pro/Audition, Acid Pro, Tracktion, Reaper, Studio One
OS X: Logic, GarageBand, Reaper, Studio One
iOS: GarageBand, Auria, Multitrack DAW, and now Cubasis
On iOS, Cubasis is definitely the best so far. Best layout, easiest to use, yet very powerful, particularly with the Audiobus implementation.