mine is a behirnger u-control £60 thing and is dead plasticy and flimsy but its lasted a year so far so i can't complain.
i know a guy with a £200 yamaha controller and a really expensive akai controller (one of the square ones with light up buttons), both of them feel solid compared to min, the keys are nice and heavy and you could probably chuck them down the stairs and expect them to work, whereas with cheaper stuff it feels light + plasticy, agree with scotty here, if you want something that will last then its worth spending the extra dollar.
like the idea, although it doesn't look like it has pitch bend or any other controls (knobs, buttons, etc), which come in handy when you want to record automation or do stuff live, so it might be a good idea to save a up a few more pennies!
ive got the nanopad (since back in october) and as expected, it does feel a bit flimsy. can take some punishment, but i always make sure its placed on a nice solid surface; im not gonna take it for granted. i just ordered a black nanokontrol; cant wait to get that in.