Got this keyboard yesterday, so I can't say anything about durability.
Overall quality is very sturdy, metal casing feels nice, knobs are very tight, touch strips are decently responsive, all the LED's are brighter than on a lot of other gear I have. Buttons are a little small and clicky, but they do the job, and they are customizable.
A nice touch of 5pin midi connector. I wish more companies did it.
Now the keys: I've had some Akai's and Novation's mini-sized keyboards, and now I can't even understand how I tolerated that junk. Midiplus x3 offers excellent keys. I've seen people complain about the size. C'mon, one buying a mini keyboard should know what one's doing. I've got it for the portability, and as long as I know that these are smaller than regular keys the quality of the keybed is extremely good. For this ridiculous price you get a piece of gear that feels premium. After Novation Launchkey Mini and Akai LPK, or Novation Mininova and Microkorg for that matter this keyboard feels real!
Pros:
Excellent value for the money
Great keybed
Tight assignable knobs
Overall feel of high quality product
Cons:
My only complaint: the CC buttons are momentary only. Would be great to have a toggle mode for them.
