Feels like a piano
You'd think as plentiful as keyboard controllers are, there'd be a myriad of choices in whatever configuration you prefer. I found this not to be the case. I'm a lifelong musician and have used my piano keyboard skills in multiple applications: recording, composing for TV, arranging, live performing. But at the core, I will always be a piano player.
As such, I want my keyboard to feel like a piano (especially for piano parts). I want the action to give me some resistance, fight back a little. So action was a big factor for me, along with two other functions. Bottom line, I was after: (1.) weighted, or preferably hammer action; (2.) assignable knobs and sliders to work with the software (Omnisphere, MainStage, etc.); and (3.) no built in sounds that I probably wouldn't use anyway, since the sounds in my software are already excellent. The M-Audio Oxygen 88 was the right combination at the right price. I strongly recommend purchasing the AC cord, as the USB power needs are demanding (my computer crashed several times without the AC cord). Very happy with this purchase.