xKeys are awesome! I have an old 20 key USB and a newer editor now also discontinued, but purchased an encoder board that I'll use to update the old hardware to work with the new software. The old editor still works via their SDK.
I'm thinking though that after purchasing a used novation launchpad, that Midi is a better way to go. I can use Bomes MIDI translator to act as the the Macroworks equivalent of the software interface, and I can get better button feedback. I don't have one of the newer red/blue led button versions, and they don't have individually controlled lamps like the novation launchpad does.
I picked up the used launchpad at Guitar center for $69, and spent $75 on Bomes Midi Translator Pro a few years back, and this is well under an equivalent 80 button xKeys xK-80 @ $230 USD.
Just sayin', keep your eyes open for a better deal/solution. ;)