I can only speak to my own personal experience.
We tried version at 37 ? weeks. It's been 9 years ago.. so hard to remember, lol. Anyway, we had my mom drive in from out of town to stay at home with our older child "just in case". I went into my ob/gyn's office at 5:00 and she hadn't flipped around, so, per our plans, we went directly over to the hospital (across the parking lot basically) and checked in.
I had an IV administered with medication to stop any contractions (I was having mild ones that I couldn't even feel) and then we proceeded. The doctor gelled up my stomach really well with the goopy ultrasound gel and started pushing around. My hubby held my hand, and after about 1 minute the Doctor stopped and asked me if it hurt really badly. No.. it was uncomfortable but not PAINful. Good. Because he was DONE. That was it. She was turned.
I stayed in that room for another couple of hours for observation to make sure labor didn't start or anything else.. ate a nice big fruit salad for dinner from the dinner "menu" and then we went home. The end.
Our daughter was born a week early (so a week to 2 weeks after the external version) and was perfectly healthy (except for a small hip click - hip dysplasia that is not uncommon among babies carried or delivered breech). She received treatment for the hip dysplasia for several weeks and has no issues there any longer. You can't tell her hips from any one else's perfectly developed ones. And that had nothing to do with the version procedure.
I had heard tons of horror stories about how painful it would be. All of them unfounded as far as it applied to me. It wasn't painful at all... and no where CLOSE to recovery from a c-section (at least from what I've heard. I had completely unmedicated natural deliveries with both my babies).
hth
p.s. When I asked my dr about all the horror stories of pain I had heard... he said that those cases were probably cases in which the dr waited too long to make the attempt. The bigger the baby is, the less room and fluid for him to move around in, so the more painful trying to do that becomes. My daughter was 7 lbs 6 oz at birth. So not big, not small. If you are going to try the version, do it soon.