PRK is less invasive (and therefore more conservative of a surgery) is it is a reshaping of the cornea, and not a reshaping of the lens, as LASIK does. PRK has about 25 years of data and history behind it, while LASIK started around 2006, IIRC.
PRK has a longer, more painful recovery time than LASIK, but long-term has fewer side effects (dry eye is pretty common in LASIK). There's also no chance of having the flap come loose in PRK. OTOH, LASIK recovery is quicker, the corrections can be a little more graduated than with PRK, and the recovery period itself is more comfortable.
Don't know how old you are or your plans, but if you're planning on entering the military, PRK is definitely accepted, and at least three years ago the military was hesitant to admit anyone who had LASIK into the physically demanding career fields (pilot, SEAL, etc.). That may have changed.
I had PRK done in 2003 (USAF paid for it). The biggest problem with PRK is it basically burns off the nerve endings in your eye that tells the tear ducts "send water." So until those nerve endings grow back, your eyes aren't wet enough. Imagine the worst case of dry eye you've ever experienced. Now throw a teaspoon of silica gel in there, and maybe some sand. For the first couple of weeks, every time you wake up, your eyes will feel glued shut, and you have to use little lubricating eye drops just to get them to open. As a result, recovery can be...uncomfortable.
But the results are AMAZING. I went from 20/70 (L) and 20/100+ with a HUGE astigmatism (R) to 20/12. Wish I had done it ten years earlier. Downside is, I can't see the rear sight on any of my rifles anymore.
I do get halos around lights at night, but they're not distracting, and I only notice them when I look for them. The dry eyes stopped being a daily problem about two months after the surgery, and by six months I had stopped using the eye drops entirely.