The pros are pretty obvious, less bulk, much more comfortable to wear, not as hot during warm weather and you can actually wear them all day long while fishing.
The cons are that if you buy a manually inflatable vest, you have to be conscious to activate it. That's not easily done in the event of a high speed accident or if you fall and strike your head.
The older automatics used to be triggered if you fished in the rain, but that has for the most part been eliminated with design changes. But it still is a possibility. A friend of mine set his down in the back of his pickup truck where enough rain had pooled and when he backed his trailer in the water, enough flowed over the vest that it triggered it.
When you buy your vest, make sure that you also buy a re-arming kit at the same time and store it in your boat, in a waterproof container. That way you'll have one when you need it.
The inflateable vests are great, but only if you're wearing it!
Steve @ G & S Guide Service and Custom Rods http://www.herefishyfishy.com


