Best cocktails goes to Dos. Volstead IMHO is too inconsistent, I've had a good drink only to order it the next time and taste is off. Sidecar has been pretty good every time I've been.
To me, I guess it boils down to consistency, Dos will always make the best drinks time and time again. A lot of the other bars are a bit hit or miss depending on who is bartending. Also, Orsay for happy hour is severely underrated in terms of cocktails available and the quality.