Couple years in on an SL88 Grand here and I continue to be very happy with it; I was a little skeptical about the "wood" action because of it really just being intermediary blocks between an otherwise normal (plastic) TP40 action and the textured keytops, but the action does seem to benefit from the extra mass, and it's admittedly nice to see wood peaking out beside depressed keys.
That texture is unexpectedly one of my favorite parts - rather than a molded-in pattern, the surface seems inherent to whatever blend of materials make up the keycaps, and show patterns that look to be the result of it flowing into the mold (making each key unique). It feels much better than glossy plastic, hasn't worn smooth or yellowed, and isn't too difficult to clean.
The control sticks were a great idea with unfortunately flawed execution; I liked the idea much better than the usual pitch/mod wheels, and the 6 available axes do offer a lot of realtime control. However, the 3 that are spring-loaded have both very authoritative center bias (it's impossible to get across the center in a smooth motion) AND surprisingly pronounced deadband, so that even if you do manage a smooth physical sweep, the encoded values would level off in the middle. They are, therefore, utterly useless for manual vibrato and anything else you'd need a smoothly centering control for
The triple pedal is well worth the price; it's solid, has an easy to modulate and surprisingly useful continuous damper while still leaving you 3 more foot control jacks.
My one functional issue wound up being the result of inadequate bus power from a USB hub, so if you forgo the wall wart power brick, make sure your USB power is robust.
In the end, it is one of the most expressive and predicable boards I've ever had my fingers on; while it may not be as much a dead-ringer for an acoustic grand as something like a VPC1, the aftertouch and granular response curve/balance control make it ideally suited for composer/musicians looking to control a variety of virtual instruments. If mine broke, I'd almost certainly buy the same thing to replace it.