Able bodied biker, just looking for something fun
First off, get a suspension seat post if you're interested in pushing the limits of this bike. Hitting unexpected bumps at higher speeds is pretty punishing, and that's all that happens in the city at 30+ mph.
Ok, so several of my friends grabbed some rear hub bikes, and this particular bike is far more powerful, faster, and it maintains the classic mountain bike geometry, if that's what you want. It's everything you want it to be. Just be safe, wear a helmet, and don't flaunt your top speed too much. But this thing is so much fun.