I have an AKAI MPK25 with is awesome for me. Only having 2 octaves at a time isn't that bad, although it is a little limiting (plus there are octave up and down buttons). It has really good construction and the keys and super solid. As for some negatives, the drum pad on it is really bad, it feels solid, but I can never seem to get a good response out of it even with the sensitivity settings turned all the way up. Doesn't really matter to me though because I don't have any need for it. Also, the presets that it has don't really seem to make a difference. It doesn't have sliders either

. They probably could have taken out the pads and put in sliders honestly. I'm really happy with it though, especially with how solid the keys feel. They're not weighted, but they're really nice. IMO
EDIT: It has nice knobs too, 12 in fact.