First thing you have to ask yourself is how important hands-on control is. The Sub Phatty has pretty much one control for each vital function on the front panel. The Bass Station II has shared controls between i.e. OSC1 and 2, ENV1 and 2, etc.
On the other hand, the Bass Station II has some other stuff like an additional LFO, and additional filter (based on the 303), a multimode filter, and some other nice features.
Lastly, if you want the Moog sound, only the Moog will do. If you don't have that specific preference, I'd really recommend you to try them both in a shop and make your opinion after playing with them.