I have Lee carbide and standard pistol dies, Lee rifle dies, RCBS rifle dies, Hornady and Lyman pistol dies, Dillon rifle and pistol dies.
I personally don't like the RCBS dies. The Hornady dies are OLD .30-30 dies, and I've only loaded like 100rds with them, same with the Lyman, I have an old .44 mag set that I've only loaded ~50 rounds with. So not much experience. But from the design, I personally don't see what makes them worth more than the Lee dies.
The Dillon dies are nice, and if I'm going to be loading on a Dillon press, I'll buy the Dillon dies in the future.
I do like the Lee Collet type factory crimp die, and have heard good things about hte collet neck sizer dies of theirs. As far as pistol dies, short of the dillon carbides, I have no reason to buy anything other than Lee deluxe carbide sets.
I do want to get a redding or Forster micrometer seater die for my rifles. Some people swear by the bushing neck sizer dies (redding and forster make them, think RCBS does too), other say they are more likely to form donuts in the neck. I can't say one way or the other.