well if you want more "direct access" to the stuff I would not go for the A-Station...it is a very nice sounding part...but the 2 Digit Display becomes quite fast a Pain in the butt...if you are into knobs I would recommend you the following synts:
Novation Supernova,
Novation KS Rack,
Roland JP8080,
Waldorf Q,
Korg MS2kr
Korg Radias,
or if you want to spend some Money:
Access Virus TI or TI Snow,
Arturia Origin,
I would not recommend you any of the Nord Series....they sound nice yes...and they offer a good bunch of knobs...but imho they are hell to program because of the triple functionality of each button...