It's one of the better companies in the survey industry. I flew survey for another smaller company in c-320s and would run into keystone guys on the road quite a bit. All the pilots seemed happy with the company and planes always looked clean and well maintained. Good way to build up your multi time, but survey is a much more stressful job than one would think. Always VFR in the most crowded, worst VFR airspace imaginable. Any IFR flying is cake compared to some of the strange stuff you have to finagle doing survey work.
QOL seems as good as you could expect with a job that throws you out on the road over half the month. The upside is they always put their pilots up in quality hotels. At the place I was working for we always stayed at no less than a Hampton or Marriott, and the Keystone guys seemed to stay at the same places.
Oh and also you could probably expect roughly 500 hrs a year.