I just picked up a left over CWB Transcend 138 at my local board shop. The rep said that the 138 length would be fine. I currently ride a 138 SOL and have done fine on it. I'm 6' and weigh 185lbs.
When I read through the forums here, it seems like most would recommend this board in a 142 length for my size/weight. This would have been the route I would have taken as well, except that the board price was too good to pass up and they didn't have the 142.
Am I really going to be holding myself back by being on a 138? Does 4cm really make that big a difference?