I would stick to the 350's. I only shoot 55 pounds, and have used both. I have never had trouble with either, until this weekend I shot a 276 pound russian boar, and my 250 broke into three pieces. It happend so fast that Im not sure of the cause. I may have just had a defective arrow. At first I though I had a pass through because I couldnt see my arrow,but I walked over and found the fletched end broke off on the ground. It did its job because it went through far enough to exit the other side, but when we cut him open, it was broke inside as well. I almost wonder if when he tensed up as soon as he was hit, if he didnt some how snap it. Either way, he's dead, but I may use my 350's if Im going to be shooting tougher skinned game like boar. Here is a pick of the arrow.
http://img.photobucket.com/albums/v94/thatsmutiny/100_2110ph.jpg