I haven't tried the Contrabands, but I have tried the Deltas with the Stealth Highback. I love the highback. It's rather thin and flat on the upper portion. Just comfortable for the boot to sit on. It also causes it to flex more towards the top of the highback.
Ride Optimo Contraband Snowboard Bindings 2011
If you are interested in speed entry, have you considered Flow bindings? Contrabands are lighter though. I've been riding Flow bindings for a long time now. Haven't had an issue with them thus far. Not even my cheap Flites gave me issues and my bro-in-law is currently using them to this day (they are 2006 models).
The ATSE would be nice for an all-mountain freestyle setup.
Flow NXT-ATSE Snowboard Bindings 2011