My opinion, and of course you can do what the hell you want, lol...
I prefer teamspeak, because then people can tell if someones in there wanting to play, and also, my opinion is that up to 10 should stay together, and just break up into smaller groups for large buildings like a warehouse with high and low ground... we could just create a blue and red sub-channel on teamspeak, in case the leader decides to split the team, since really his choice... then hot keys can be made to jump to whatever channels.
But I'll do what the team wants.