CASH TITANS uses NATS, we love it we used to me on MPA2.
I find that NATS is a lot more versatile we are able to use more then one join page template for one that was a real pain in the ass before as every join page looked the same and well that really doesn't work when you run a hardcore gangbang facial site and you run a softcore single girl site. since the hardcore did 10 times the joins we used the hardcore template for the join page. That was just one of the issues I had with it.
I love Oystien and Garry and I have known them for a long time. great guys! We just were not happy with the software we purchased from them! We have now moved to NATS and we like it very much.
As for MPA3 I didn't even look. In the last four months I have been working with a program that ran on MPA I could not get webmasters to join, they didn't trust the system. Now that we are on NATS its a whole different story. I have had more webmasters sign up in a week then did in 4 months. MPA just has a bad stigma attached to it and I had to move away from that to make money.
I think MPA has to clean up their name. They will in due time but I think it will take some serious work. its not going to happen overnight but I think they will!
As for cashtitans its running very strong we had no problems making the switch to NATS and we are very happy with it.