That sounds like a reasonable price. The BMW head is especially difficult to take apart needing many special tools. I would use price as only a second qualifier though. You should only be checking people who do this type of work often.
We charge 15 to 20 hours to do the head work necessary to repair it right. The difference is in the amount of valve work and number of valve guides necessary (when the valves bend over they often expand the bottom of the guide; not replacing them gives very short valve life). If you mulitiply those hours by 70 you get 1400bucks, not much for parts. I would expect anyone in LA that does that kind of work often would get at least 70 per hour. This is not a good place to try and save $200.
Price some quality shops (go there and be sure they only work on German cars and there should be plenty of good BMWs onsite).
Bosch Master, ASE Master, L1
33 years MB technician