I recently test drove the Audi TT with the "paddle box". Had it for 24 hours and used it.
a) downshifting is REALLY great. Like a manual, I swear. VERY COOL....no delays or nothing and if you want it in first it will go to first and buzz the engine (ooooops....sorry about that Audi)

b) the upshift.....a complete POC.....just like any other pseudo box.....POC......but then again, who cares.......the TT got it right......cool downshifting if you want, and auto for the rest.