Simple misunderstanding, he made an error. Give the new (well, sort of?) guy a break. He apologized for it as well.
Anyway, on topic: I'm pretty much solo/coop. I definitely prefer coop, as I love to share my gaming experience with someone else. "Did you see how COOL that was?!" .. and such things. Being able to support each other and not having to deal with AI. There are plenty of games I wish had coop..... sigh. Damn you, Stalker. On the other hand, 2008 seemed to have been the year of coop, and even the new Total War game will feature an online campaign (= coop!).
Otherwise, it's solo for me. I can't stand PvP. I hate it. Hate hate. Hate. I don't like competition. I'd much rather cooperate.