I forgot to say - Dirty Bomb uses official (as in you can't rent them) dedicated servers, with a browser to pick the region/first map. After that, it is matchmaking with lobbies. There is also a "Quick Match" button, which isn't working too well during the beta. I habitually pick the Euro servers, and get an average ping of 40. So, that suits me. I have never seen my ping dip, even when it's busy, which tells me they are using quality servers and not ones that get over burdened easily.