Adam,
With 223 in a bolt gun, you don't need to crimp.
Since it is a bolt gun, neck sizing is an option, and the Lee Collet neck sizing die is really good.
If you want to full length size, the RCBS X die is an excellent choice.
For a seating die from one of those two, I would prefer the RCBS competition or gold medal series windowed seating dies, but they are more expensive than their standard seating dies.
For just a standard set of 223 dies, between the two, I would go with RCBS, mostly because I'd have to replace the Lee lock rings with ones that work.
But for just a little more money, Hornady has a much better seating die in their standard set, and the best lock rings on the planet.
Andy