I love the Redding Competition seaters. they are great for calibers where you load several different bullets. Just dial it back to a recorded setting and go. Loads rounds straight too.
I have many more Hornady seaters in pistol calibers because they work great and are much less expensive.
I have had two out of four, maybe five, carbide rings come loose from Redding sizers. I have never had that happen with Lee or RCBS and I have had more of those. Go figure.
I like the Redding two step expander that they copied from Lyman because it does not bell the brass excessively and I believe it helps bullets seat straighter.
My 9MM, .38, .357, & .40 die sets have Redding or Lee sizers (Yep-Redding replaced them), Redding expanders, and Hornady seaters. My .45 ACP set has the Redding Competition seater. I load several different bullets in .45ACP.
I really like RCBS dies and have some full sets, .45 Colt is one, 400 Corbon is another I can think of offhand.
I have Lee sets for .32 ACP, .32 Long, .38 S&W, that I can think of anyway.
For rifle dies I like the Forster sizer with the elevated expander ball, although Redding & RCBS sizers work great as well. I like the Forster seaters and the Redding Competition seaters. I don't have any Redding seaters myself, but have used them. I bought Forster seaters long before the Redding Competition seaters came out.