The NP-11 is (I believe) a synth action keyboard. If you want something with a bit more heft you might look at semi-weighted keyboards. Be aware that many semi-weighted keyboards don't have any built in sounds (in which case they're called controllers). With controllers, you need to hook them up to a computer (or ipad, or sound module, etc...) in order to generate sounds. If you want to get something that is both semiweighted and has built in sounds the cost seems to go up significantly.
What's your budget? if you're looking just to spend a couple hundred bucks then you're probably going to be stuck with a semiweighted controller plugged into your computer or iPad. when you get up to about $1000-1200 US you can get something like the korg krome or the yamaha moxf6. Those are several times the cost of the NP12 (don't think they make the NP11 anymore), but they do have professional quality sounds and features.
Next up would be fully weighted keys. I'm not aware of any 61 keyboard that has fully weighted (like a piano) keys. The closest would be Roland's RD-64 (which has 64 keys). It's about $900 US right now. It has a limited set of sounds and features, but it's a lightweight (28 lbs) board with fully weighted keys.
