Well, I have been quite pleased with ModernBill lately. There are still some quirks.. but overall I am very pleased. It has handled our business the way we have expected. Now, the hardest part is to get all of our customers moved. Our old billing system is so screwed up, that its hard not to have Garbage in, Garbage out. I am waiting on a new release of their software which will include some long needed fixes. They still have problems with Plesk and creating 2 or more accounts for one user. I have done a lot of complaining about it, but we are not very pleased with Plesk anyways, so we may dump it.
We noticed that hostgator is running an older version of the software (4.x) and we are running 5.x. That made us happy to see that a major competitor to us is using software that has been "questionable" at times.
I am hoping that this will continue to become a solid product over the years, as we are making a considerable commitment to use it and move all of our customers into it.
www.amhosting.com will fully provision all the hosting and domains without our interaction. It handles all the fraud detection (which is a MUST).
There are a couple of people over there that you really need to become friends with. Kris is by far my favorite person to work with. He goes above and beyond for his customers. Another that appears to be trying is Sarah and Blake. Kris by far is the top guy though. I wish he was in charge of the place sometimes so he can get some things done that are desperately needed.
I will be doing an upgrade soon. I will post on how well that works.