My 2 cents..
The acheivments are a nice idea but the killcam has completely removed the 'pro'-ness of the game. I can't quite put my finger on it but the accuracy of all the weapons feels very different. The one thing I really don't like is the sheer laziness of the update, like DoD, they have just tacked on some stuff, no extra artwork or anything bar the now hideous menu background.
The killcam is rubbish too. It works on TF2 because of how animated the characters look and the random nature of combat. On CS:S and DoD it just highlights how dated the player models are. I personally think they shouldn't have bothered, if it ain't broke don't fix it, should have waited a year and released CS:S:S or something.