I chose the Impulse 25 over the Remote SL 25 mainly for the piano-style keys, although it is a lot lower in price too It also looks and feels far more substantial, it actually looks like a really cool synth in its styling, and build materials are excellent it is quite a sturdy unit.
The key action is the best I've experienced on a controller.
The LCD display and mod wheel are gorgeous. Aftertouch is excellent, and as the keys are the chunkier, piano-style keys, you don't feel as though you are going to snap a key off when you press down to trigger aftertouch, as it sometimes feels with, say, the thinner Arturia keybeds.
My only gripe is that the relative lack of sliders and trigger buttons makes soft-synth control quite limited, but obviously that is the trade-off when getting this smaller unit. I do wish they would produce a 37 key version though!
On the whole very pleased with this, it lives up to expectations and the new Automap 4 software is much better then it used to be.