My dog had laser therapy for a muscle pull (rehab specialist at the University of Florida vet school is very big on laser), along with ultrasound treatment- I think it was $75 for the combined treatment and he was prescribed 2-3 treatments a week for three weeks. My regular vet uses laser therapy as well. Many people in agility use it for various injuries. The main pro is that it's a non-invasive treatment for many injuries, and I don't know of any cons.
Mikko (USDAA) MAD, SAM, GM, RM, SJ, SS; (NADAC) EAC, EJC, TN-E, TG-E, WV-O, OCC, HP-O, VerO; (AKC) NAJ, CGC; NW1 - 7 year old GSD