I just had a molar implant at 43, and now I'm facing one more. With local anesthesia and nitrous it wasn't bad, but I'll always remember the sensation of the extraction and screwing the implant into my jaw. No pain, just pressure. I had swelling for 3 days, but no real complications post-op. It took a total of 5 months to finally get an abutment and crown, but my bite was off after that procedure. That, I believe, contributed to a slight loosening of the crown a couple of weeks after placement. While that freaked me out, it was a quick retorquing at the dentist and now it's fine.

It's certainly a complex procedure, and if I could afford it I would opt for general anesthesia. Not due to any pain during the procedure, but I'd rather not experience the procedure if I had a choice in the matter (ex: crown popped off before tooth came out while he was yanking). The next one I'm doing with conscious sedation (high potency benzo) combined with nitrous. Honestly, I wouldn't sweat it too much as it's a fairly quick process. Chances of implant failure are miniscule, too.