For the price, it's a good entry point to the world of fast primes. Punches well above it's weight, optically, but build quality is very poor. The Mk1 is better and has a metal mount, but these are only available on the used market and cost a bit more.
50mm on a crop body has the same field of view as an 80mm on full frame, which is getting into short telephoto territory. I hear it's useful for portraits but have no personal experience of this, and I think it's too long for a walk around lens, but that's a personal view. YMMV.