I've had Jimmy Lewis paddles since he started making them. First of all, these are not like other fiberglass shafts. Jimmy went through all kinds of shenanigans to get what he wanted. Why he wanted it is a little strange to me, because no one else was headed in that direction--he wanted a shaft that would flex and be bulletproof. the blades are from Jim Terrells Quickblade molds but they are fiberglass as well. First time I tried one I said WTF, it felt like a wet noodle. I persisted because at the time my shoulders were killing me, and I hope the JL would help--Jimmy said it would.
Basically I can paddle all day with the damned things, either blade, and never feel a thing.
There's two old articles on Ke Nalu about the JL paddle. Here's the URL for the search result
kenalu.com/index.php?s=jimmy+lewis+paddle&x=0&y=0 there a bunch of extra junk that comes up with this search, but the first two articles are the ones you want.
As far as strength goes, take a look at this picture of my friend Johnny Karamanos putting the hurt on this paddle. If you did that to a Carbon Fiber shaft it would be two pieces. Notice also how smooth the curve is all the way to the blade tip.
In short, these are very worthwhile paddles. They are very different, and not everyone likes them at first, but I see a lot of them out in the surf, and folks who have them and get used to them really like them.