It depends... Usher's new stuff has been really great lately, plus he gave us Confessions and a couple of other really great songs.
Maxwell's consistent; I haven't listened to most of his work, but BLACKsummers'night was an amazing album.
R. Kelly has probably given us the best overall song out of any of these guys with Ignition (Remix)
Trey's decent' not bad, not great; same with Ne-Yo. I won't comment on the other one seeing as I don't need Warning Points.