Right now I have:
Nektar LX 25 mini
Nektar Impact GXP61
Novation Launchkey 37 [MK3]

- I wouldn't get the mini unless you were short of space. I bought it because I thought I couldn't make the 37 key novation work in my space but I did. I'm keeping it around as a backup and maybe to use on my treadmill desk with an ipad.

- Impact GXP is a nice keyboard if you don't need pads. Decent synth action, no problem with playability. Has aftertouch. I'm actually thinking about getting the 88 key version. If they made this in a 37 I probably would have purchased it. Part of me wants to buy the 49 key to have a little more room than on my novation.

- I bought the novation because I like 37 keys better than 25 for smaller keyboards, and I had a novation in the past. Maybe I'm just nostalgic but I don't feel the same quality that I did with with their previous keyboards. No aftertouch on the keys, but there is on the keypads.