I just wanted to come back to this thread and say I rode today for the first time w/ my Charles Owen JL9 Vest and I was very happy with it. It was heavier and sturdier than I expected, but it did not interfere with my riding. The only con I saw was that it's hotter wearing the vest. This isn't so bad as I was riding at 7am but mid summer day I could see wanting to rip it off.. :)
But I will continue to ride with it. I value my body too much and always hear horror stories. I tend to lean on the conservative side safety wise in general, but you can never be too safe IMO! Just today I learned a rider over the weekend fell and ruptured her spleen. !!! So scary. But can't... stop... riding...... :)
Re: any of my advice - Happy to give my two cents, but not an expert... just a girl who loves riding horses!