@wish - and anyone else on the fence for sizing of the Impact vest. See the below that I copied in from getagripwatersports.com. I guess I'm going to keep my medium and wait till warm weather to try it out. Worst case: I'm out $30 ($40 purchase less the $10 I'd have spent shipping the return back) and someone I know gets a very nice slightly used vest. With any other comparable option costing $140+/- I reckon I might as well give it a shot. This is a really cool vest at a steal of a price so if it just does work out that leaves me $100 to otherwise support the habit! By the way, as far as I know, the blog post below would have been made well before anyone's stock got low, meaning they had plenty of larges and bigger to pick from so they probably weren't just trying to unload a bunch of smaller sizes.
"One of the owners of Get A Grip Water Sports is 5' 10", 170 lbs, and typically wears a 40-42 Regular suit jacket. He also fits comfortably into 2010 and 2011 medium Radar Strada vests. When the 2012 inventory arrived, he first tried on the medium 2012 Decibel, it was too tight...on to the Large...too tight...and then on to the X-Large. The X-Large felt good on land but, once in the water, he realized the X-Large was too big. He tried a Large in the water but, still to big. The large was a marginal fit but, potentially, medium would be better.
So, back to the medium, this time an effort was made to actually zip it up. After a little work, the vest was on and felt OK; very tight, but OK. Once in the water and after a couple sets, medium is what he settled on.
Please keep this in mind: When new and dry, the Radar Decibel vest MUST be tight; otherwise, you will not be happy with it in the water."