As a total newbie, I am very interested in this topic, mainly because I cannot afford to buy both systems. I have to buy everything all at once. These caddy's or the L2/L4 are $50 each. Get six of them and that's $300. Decide you made a mistake, and double that. I can't buy $600 worth of caddy's, and the closest 3-gun range is 3 hours away so I can't exactly try somebody else's out.
From what I can tell, the weak hand reload is more practical. It's what LEO's are taught, I could see it being practiced at the local skeet club without being totally laughed at, the caddy's could probably be used while hunting in some situations, etc. But doing this a lot when you are new to 3-gun and have carpal tunnel is slow and painful.
The load 2 method seems fast in itself but I'm skeptical because of a few reasons:
1. Seems like there is a lot of awkward movement of the shotgun to get it into position. Throwing it over your shoulder or flipping upside down just seems unnatural.
2. If you use the strong hand version, from what I can tell, your shell holders are right where you pistol holster needs to be. Not sure how you're supposed to deal with that.
3. the top guys are still using caddy's. If they're not, the wording of their endorsements sounds like their sponsors want them to push it more than they like it personally.
4. Not sure how going prone is supposed to be possible. If you empty your new shiny AP L2 then have to grab a rifle and go prone, or even have to crawl under a car and fire your shotgun like in St. Louis, what's keeping you from destroying the metal arms that hold the shells? With a caddy you're just sitting on an aluminum box, you're not going to do jack crap to it. An AP L2/L4 though, I can see those metal arms getting bent.