Left4Dead was gimmicky and shitty... a polished turd. The campaigns had incredibly limited replayability, and the only really major difference between each playthrough were the Tank and Witch spawns. As a shooter, it is incredibly simplistic, the versus mode is unbalanced and the 'free expansions' are pretty much just rubbish. The Crash Course thing was just some left-overs from the original process that was tacked on. As for L4D2 and the Boycott, I got into an argument with one of the founders... and was convinced that he's nothing but an overzealous twat that thinks everyone is in EA's pockets or something retarded like that. I would not trust his opinion on the sequel. From what I can see, L4D2 is a massive departure form the more darkly style of the original, venturing into the lands of what almost appears to be Team Fortress 2; more colors, more silliness, less horror... not that the original was scary, either, but at least the stylistic content was alright.
L4D was not worth the initial 50$ price tag, but for a 20$ game it is fine. L4D2 is too similar to the original, with most of the foundation having already been laid, and wouldn't be worth more than 20$ either, at most. Might buy it at a discounted price... otherwise I'll pass. FEAR 2 and Killing Floor had a lot more bang for the buck.