I played some TFC on Quake a long time ago.. TF2 is basically the same thing with better graphics and a better balance.. if I remember well, the original mod for Quake didn't had the same variety of maps and the classes weren't well balanced, Valve did a great job reviving this classic.
And I really liked the cartoony style of the game, found it very creative.
The cartoony look actually works here. Since the weapons aren't very accurate and it takes alot of hits to kill someone, the look and feel fits perfectly and actually makes for an enjoyable experience. Now if they only made CS:S and DoD:S look the same, then those games would work. Or the easy route would be the make those guns accurate and do some real damage.
It is a shame TF2 isn't realistic looking like it was supposed to be originally but it is a good game.