I have the 550b and the SDB presses. As stated the SDB only will load certain pistol calibers. It takes a little more effort to work the handle on the SDB compared to the 550b. The 550b has greater leverage because you can also load rifle ammo with it. The SDB works with very little tinkering. I suggest always getting the strong mount with the SDB press. The 550B will mount to most benches without problems. You do need to have about 1.5" of over hang on the bench top. If you don't have any overhang and don't want to add it get the strong mount for this one as well. The 550b is slightly faster than the SDB press but not by much. There is a little more room for your hands to place bullets and cases on the 550b. The powder measures are the same on both.
I prefer the 550b press over the SDB. Both do work. I have the SDB only setup to load .45 apc large primers. The 550b is used for small primers in everything else I load. I have tried the Lee a LGS had setup for demo purposes. Either Dillon press will be much easier to operate over the years compared to the Lee. Once you have paid the money for a press you start getting over the cost fairly quickly. Having to tinker with a press constantly to produce any ammo gets old pretty fast. The more you have to tinker the worse it gets. I like being able to call Dillon if something fails to be told the part is on the way. I found if you just send an E-mail about needing a part it will take 2 to 3 days longer to get it compared to just calling. Dillon's customer service is great.
I got my presses from Brian Enos. He ships for free on orders over $400. The caliper (digital) he sells have a lot to be desired. Everything else I have gotten has been great.
I think if I were to sell either of my presses today I could get what I paid for them. If not the difference would be small.
Last edited by Misssissippi Dave; January 20, 2013 at 01:10 PM.