When I first started reloading with a single stage press I was using Lee dies. When I finally decided to jump up to a progressive, I choose the Dillon 550 and am extremely happy. The only possible problem I see, and it moght not be a problem at all, is that you have to scrw in the Lee dies almost all the way to fit them into the Dillon 550. I have Lee dies for 9mm, .40S&W, ad .45acp and they are all the same way. I have also purchased Lee Carbide Factory taper crimp dies to add to my 4th stage of the press. Right now I am still playing with things a bit, especially with the taper crimp. I just can't seem to figure out what is quite right. My question is, any problems with how far I have to screw the Lee dies into the press or are there better choices?