I think the real test and deal breaker here for me is this; 1. Are there dedicated ZA servers for Multiplayer? 2. How big are the maps?
Yes there will be dedi servers in SA at some point. I have pre-ordered 2 servers from gameservers.com while i wait for local availability. The cool thing is that if you are playing a single player game and when starting the game you choose public game, your server can be joined by other people and drop in and take place of one of the bots. It works quite well and a mate and i have tested this. Im not sure if the server lists on the master server list but i will try comfirm this. A 4meg line can handle around 8 - 10 people from what I have read up on bandwidth requirements.
The levels are quite large yes, and pretty complex with lots of nooks and sneaky places. The level design is great i think and it really creates some nice firefights.