I hated their choice of gimping the 360 version (even if with minimal content), so I'll boycott this game. Was going to buy it for sure, but now it's a no deal. Too bad for me and for them... but oh well, whatever.
While I respect your choice, it's a silly one without a doubt. You are going to pass on a great game, possibly the best game this year, just because the other version got one "outfit" and one "shootout" for online only?
There have been tons of games on the 360 that had exclusive content, there were games that had some on the PS3. By boycotting this game you are not punishing the developer or publisher, you are punishing yourself, because you are willingly passing on one of the best action game experiences and the best sandbox game to date.