Well, what everybody is saying is true. It's a lot like Chuck, but better than Chuck. It's funny and yet it's got some nice dramatic moments too. It's got likable characters (I'll take the actually funny sidekick in Reaper over the annoying sidekick on Chuck, and Missy Peregrym is terrific as the hot yet accessible love interest), a fun premise and a general tone that reminds me of everything I liked about something like Buffy without seeming like a ripoff of Buffy.
And it's got Ray Wise as the devil, which is pretty much a good enough reason to watch the show all on its own. Kevin Smith directs the hell out of the pilot, but I have to say that I'm hopeful that other directors can pull off similarly good work with the show as it goes along. The special effects weren't blow the doors off expensive looking, there weren't a ton of fancy camera tricks or editing tricks (although a good editor, and someone good at the music choices and cues, is gonna be crucial)... the heart of what makes this all work is the cast. Good cast, good writing, good premise? Few shows this season have more than one of those, so far.
Oh, and I laughed out loud several time. Not only is the show imaginative and well-acted, it's *funny*.
I haven't seen Pushing Daisies yet, but Reaper is looking like my favorite new show of the fall.