I found the quality of the build to be a little flimsy. The handles on the faders come off really easily and one got lost in the box. Took a total of a week before I lost the slider alltogether.
You have to update the firmware straighaway when you get the keyboard and this is not only a fiddly process but you cannot operate the damn thing without doing so first. Configuring Reason to work with it was a pain too, despite presets being available.
It's ok. I actually use it as a normal keyboard and assign midi macros the keys, but don't count on it as a devent controller for Reason.