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DON'T buy an Alesis; they have the worst keybed money can buy, seriously. I've tried MANY, and by far the best for playability is the Korg Taktile series. They're not being made anymore, but you can still find used ones on Ebay or Reverb.
R
Alesis is part of the same inMusic group that sells Akai and M-Audio. They have several levels of gear and they probably get their keybeds from the same places.
I have an Alesis VX-49 (VIP compatible) and that is a step up from the old M-Audio Axiom-49 I had for years.
I probably wouldn't want to gig with an Alesis, but for home studio users it should work well, and it does fit a lower budget point than the more rugged gear.
I have an old Alesis QS-6 synthesizer, and the keybed on that one is solid as a rock. But obviously it is no longer the same Alesis company that made that one back in the 90's. inMusic has bought up a lot of companies and is now trading on the names and trademarks of historically significant music equipment manufacturers.
Comparison shop carefully and try them out in stores if possible, or at least purchase from a company that allows returns.