I'm a veterinarian and have performed stem cell therapy on multiple dogs at our practice in Olathe, KS. We used Vet-Stem and I feel it's the safest and best. Some places offer "same day" stem cell therapy, but be cautious with these, as I feel the quality is not as good. I recommend stem cell therapy for relief of arthritis pain when surgery is not an option or would not likely provide sufficient pain relief. In all honesty, we have had mixed results. You can read about the individual patients we've treated here:
I definitely feel our younger patients did better than the geriatric ones. There's some additional information on our website about what's involved, and there's a video too. My own dog was the first dog in the state of Kansas to receive stem cell therapy, so I'm really a believer in it! At our practice, the procedure is about $3000 when all is said and done. A new option, called StemInsure, is a good way to go for younger dogs that may develop arthritis later (e.g. the hip xrays indicate dysplasia but no arthritis yet). It involves collecting a smaller amount of fat, which is stored at VetStem for future use. When you're ready to use it, they can culture the cells they need from that sample. The nice thing about doing it that way is you're using the younger/healthier version of the stem cells, not the 8- or 10-year old version (or however old your dog is when he has the full procedure done)--stem cells age too, and aren't as potent in older animals.
(Sorry, we're not in driving distance but hopefully this information is helpful!)
Olathe Animal Hospital, Olathe, KS (where I'm a veterinarian--Dr. JC Burcham)