It all depends on what you need to record. If you don't record and just mix get just a volume knob. (I have the Kii controller and that's it). If you do record think of what you record, instruments (DI), synthesizers (line in), headphone outs for your band members etc.. apollo is a very expensive option for what it ends up actually being. I would personally never do that and opt for audiogridder. Long story short, think what you need and if you mix analogue, record or are just like me.
Good luck!