Having played TF2 from day 1, I have to agree with your description of enjoyable gameplay, but there were bugs, massive blunders both in map design or character interaction. Who can forget the infinite uber exploit or sentries located below map grounds. In valve's defense, the game was always user-centric. Fun, very friendly to community and a great value for the dollar.

We were administrating 4 TF2 servers and updates to the servers were almost a weekly occurrence. Was it worth the hassle : yes. Valve knew how to handle community issues and provide a product that players wanted. I don't think it's easy to hold a lot of game companies in this high regard.