I would like to know which Billing/Support Addon System do you use, prefer or look for! Please feel free to comment on them if you wish, thanks for your time.

Have you had any issues with one of the following? That I should know and be aware of before getting involved into the system?

ModernBill all the ways :)

WHM autopilot is best imo

Cheers for Modernbill :)

Modernbill is the best route to go in my opinion! There are soo many features and you can do a ton of customization and integration :)

Modernbill all the way.

I have tried them all:

PHPcoin
ClientExec
WHMAP
Lpanel

NONE of them even come close to Modernbill as far as the features and automation.

The rest are fine if you have basic plans without multiple choice add-ons, but if you offer plans that can be customized, then only Modernbill will do this without making a mess of it.

Whois.Cart is good, but I am too irritated with it at the moment to get it to work properly.

I seem to have major issues with the lack of customer support the Lpanel Team is having is there any issues that you may have heard of in either Lpanel or others. How is the support team for each system?

Doesn't matter getting opions form thers on this. There will be some WHMAP fans and some MB fans and some CE fans and some Whois Cart fans. It is all your own option.
There is going to be opions on both. Ither is good but they are used so much. A custom script makes you look much more professional. Since every 1/3 host is ither using whmap,ce,mb,whois cart. It is really getting boring seeing all these people having the same script.

I am really just looking for experinces with these companys, I take all opinions highly in making a decision. But I do not want to get burned like I did last time so that is why I brough this question up.