Feature:
Well it's really just an add-on feature for the triton LE, but having 2 Line inputs is great, plus the scsi interface could be useful (haven't used it). Also, it adds capability to load samples, so you can download the sounds from the exb expansion boards and get the same sounds without paying for the boards.

Value:
Too bad the keyboard didn't already come with this thing installed, but I have not once regretted paying $200 for this board.

Desirability:
I wanted it and now I have it. I haven't looked back. It is a must-have.

Sound:
I'm no sound expert, but it does replicate the sound exactly. Sample rate is something like 16 bit 48Khz

Ease of Use:
You might want to read the manual to figure out all the sampling options, like how to edit waveforms and add effects and map samples to different keys. But it's pretty straight forward once you get the hang of it.

Support:
Haven't needed to use it.

Overall:
It adds a whole new dimension to the triton LE, allowing you to add new samples, or download different samples (maybe even the samples from the new Korg TR) to get better piano sounds or Van Halen's "Jump" synth sound. I don't know what I'd do without this expansion.