The midiman keyboards are just as midi as those other brands. The only difference is that they offer a USB interface, aside of the midi.
So they have a midi out, just as those other boards, AND additionally, they have a USB-out. So you can directly connect them to your pc too, without the need of a midi interface...
So, brzilian is kinda wrong here.
But it might be a good idea to make sure that the device you're gonna buy doesn't just have a usb interface. The midiman keyboards have a midi out, I checked that.
When you're looking for a midi keyboard, what you gotta look for is: the number of keys you want, whether or not you need a midi-input on it (for daisychaining multiple keyboards, sequencers,...), the number of knobs you want on it, pitch wheel or stick, number of splits you can do, regions etc, the touch you want. That's about it I guess...