the best chat software

[NSDJgj]

Hi,
I'm a webmaster, and I want to add a chat room to my website vBulletin 3.8.
But i don't know what's the best chat software for website?
As a user/customer, what are the top there things you are looking for in a cloud provider?
Some of the probable parameters:
1. features
2. Cost
3. Payment flexibility / pay as you go options
4. performance
5. support
6. service
your opinion is welcome, thanks in advance!

[Anupam]

Hi, welcome to the forum.

Please note that we are a freeware forum, and only freeware/free software will be discussed here. If you are looking for discussion on commercial software/service, you will have to look somewhere else. Just informing in advance.