Well wayplo, it all depends on what you really want,for a controller MIDI,any can work at a very basic level,but the type of keyboard seperates the sheep from the goats.It's like this,the K2600xs is probably the hottest synth/workstation/sampler on the market.
The XV-88,rolands' heavy hitter ,is bascially an all in one sound provider,without the luxury of sequencers/deep synth architecture....sampling etc.
So ,there it is,all laid out in a nutshell,but to be honest from what i've read of your profile of future and present endevures i'd recommend the K2600XS,it has a steep learning curve,and i'll be upfront about that,but being a minimalist at the moment,you'll do best to have it,for not only you;ll have probably the greatest all synth architecture V.A.S.T + triple mode +KB3,but you'll also get a superb onboard sequencer.
But as i said,it's only an opinion based on the info you've given me.........you have to make the final choice !.......good luck !
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