I've used several different stretch type belts. I like the comfort and quick release buckle designs must of them have. I also like the set it once and forget it idea behind them, though some are better at that than others. Here's my take on the ones I've tried.
Eddie Bauer Genius belt. Too much stretch and wouldn't hold its shape and slipped quite a bit. I wouldn't recommend it.
Marsupial Belt. I quite like them and own a few. They are great for the money. Stiffer and less stretch than the Eddie Bauer but they do slip a bit and lose their shape over time. Not great for carrying weight like a pistol, but decent all around. It will pinch a bit under a pack belt but it's not terrible for me. I like the quick release design of the G hook buckle but it's not as good looking as some other options.
Arcade belt. Super stretchy and soft. Not nearly as much structure as the Marsupial but very low profile and comfortable to wear. If you need to wear it under a pack belt this one will work better than any other belt I've found for comfort in that situation. Wouldn't be good for carrying a pistol.
Groove Belt. For everyday wear this is my favorite belt. The buckle design is pretty cool and you can get different designs that look pretty classy. The belt is slightly stiffer than the marsupial but has been holding its shape much better over the year I've owned one. That said, the buckle isn't quite as low profile so it's not one I'd be using under a pack, but for every day use I really like it. Still probably not quite enough structure to carry a pistol but getting closer.
All that said, my concealed carry holster (HAWG Holsters) uses a clip that attaches directly to the pants themselves behind the belt so the type of belt I use matters much less for me in that regard than if I were using a different holster. I think it's called an Ulticlip.
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