There's a lot of more technically capable stand-alone gear that can be had for less of course. My MPC Live is what my finished (not good compared to others, I'm just an amateur making video game soundtracks for kids I teach game dev to) songs ultimately come out of, and the Octatrack is something I've really enjoyed playing with. None of these are going to be something that lives in my backpack and comes out in the park on a sunny day when I've got that perfect boss battle intro sequence drop popping into my head though. Size considerations aside, I can slam down a decent prototype of a song that's actually listenable in just a couple of minutes on the OP-1 before the idea fades away, and have a blast doing it.
I think their pricing is sensible. The thing fills a niche no other piece of gear I've found can. That seems worth paying for.