Don't ever be tempted to go the extra mile like I've done on a couple of occasions and ended up having sex with the clients. To my horror every intimate detail was shared on punter forums and I had clients since then expecting the same things.
I agree with LOTM! I started out doing massage/happy ending and found that a lot of customers pushed for extras. I too made the mistake of going farther with some (RO and full sex with a few) and each time I did they would post the details.
There were some that made it feel like a contest--how far they could get me to go. Not that this doesn't happen to me now that I'm a full service provider, but the vibe was different. Not sure how to explain it.
There is def a market for massage/happy ending but the prices are lower for most in my area.
I'd also recommend taking classes if you haven't. The quality of your massage will often be reviewed and many are truly looking for a therapeutic massage, not just the happy ending.
Best of luck in whatever you decide.