it all depends on your system ram,speed, and connection. I can easily host 8 people but after that it becomes unstable.
Another lag factor is non-dedicated servers, If you see someone with 0 ping in game ya might want to look for another server to play on.
I make my server dedicated, then I goto gamespy and join it.(its the only time I goto gamespy cause Im not smart enuf to get it listed in 'all seeing eye' yet.)
