PHPLive does have a lot of features, but it does have some issues as well. At my last job we used it for about 18 months, no major problems and their support is pretty good about answering tickets quickly.
There is actually software I had the opportunity to test-drive. Its called IntelloChat and I believe, its part of IntelloDesk upcoming software from AvidInteractive.
Its very neatly done, performs well and you can customize it the way you want. I think I'll grab one license when its released.