I'd have to disagree. They shoot well in Rio hulls and any other one and done hull. You can use them in a nicer brass base hull but the pocket won't hold a US primer afterwards. I usually find them cheaper and more often available....
I've used them in AA, Remington, and Federal hulls with great results. Like some of the other guys said, they are slightly larger in diameter than American primers and will stretch the primer pocket slightly to where it will not hold an American primer anymore.
Rio primers are a larger diameter than the Winchester/Remington, etc. They will enlarge the primer pocket, so you may not be able to use a different primer in those hulls after. It's also designed for a large, straight wall hull, using powders that are not easily available in the US. They are also a bit on the HOT side. I would treat them like the Federal 209A or CCI209M primers, since they are pretty hot themselves. They work fine in cold weather. When used in the federal rolled paper based hulls, it can get you an additional loading, since the base will be loose on the Federal primer after the first or second firing, having the potential to leak gas past them. The Rio will be a tighter fit.
Just be careful not to swap them without doing a little homework. There is a bit of data out there for them, but if making a substitution, make sure your load has enough headroom for a some extra pressure.
When used in the AA or Remington Hulls, I would treat them as the hottest primer you could obtain. In a large hull like the Federal Gold Medals, it may make a little less difference. I would mention that they could be loaded in the RIO hull, but I don't load them, nor do I shoot them when new. Lot's of people like RIO/Kemen or similar shells, but they are not my favorite flavor. To each their own. The RIO primers do seem to work well, so if you can get by with enlarged primer pockets, they are a good deal.
I have had nothing but trouble with both Rio and Nobel primers. Thought I would reload Nobel hulls once and pitch since there are so many of them available for nothing. Tried both Nobel and Rio primers with Titewad and Red Dot. Everything from off sounding shots to pops where the wad does not clear the barrel to outright duds. 7/8 oz 18.4 gr Titewad, Claybuster WAA12L clone, Nobel 209 primer. I tried them in AA, Gun Club and STS hulls as well and they don't work any better. If any of who who like Rios and Nobels have a 7/8 oz recipe that works, or better yet, works in a Nobel hull, would like to see it.