You might wanna upgrade to a more expensive 550 or 650 if you are going to do a lot of caliber changes. The SD press (I have one) is a royal PITA if you wanna change calibers. I gave up on the idea and bought a cheap Lee Pro 1000 off ebay. The Dillon is a better built press, though, and the customer service is the best in the industry hands down. If I could afford it, I'd have a square deal set up for every caliber, but that'd be half a dozen presses and not to mention some calibers I load multiple bullet/powder charges.
I can't knock the quality of the press, though. It's hell for stout and a quality tool.
I looked into caliber conversion for mine to .38/.357 which I load a lot. It came out a lot cheaper buying the Lee off ebay because it uses the Lee dies I already had and caliber conversion is a couple of minutes. Just looking at the SD, I'd have thought more like a half hour minimum, LOL. All you do with the Lee is pop out the die holder, take off the plate carrier, and swap. Requires one allen wrench. Both machines have their quirks. Loading the primers in the SD is a bit more of a pain. The Lee's primer feed has its own routine, but if you know how to feed it, works fine. Just can't leave it alone until it runs out. Dillon has by far the best built quality, should for $250.
Ebay got all anti gun and no longer sells gun related stuff. So, if I get a caliber conversion in the future for the Dillon, I guess I'll have to pay full midwayusa.com price for it. However, I may convert it eventually to .38/.357 because I load more of that than 9mm anymore. I'd like to keep the Dillon set up for loading what I load the most because I prefer to load on it. It's more trouble free, less to watch as you crank the handle. LOL However, I'll have to reset the powder measure every time I change loads. Don't have to worry on the Lee, just swap the powder disc to the proper sized one. I really like that disc measure thing, quick, simple, and accurate. I do have an electronic balance now that will take some of the pain out of setting up the measure, though. Problem with setting the Dillon up for .38/357 is that I have like 6 regular loads for .38/.357 all requiring different powder charges and bullet seating die heights and such. Easier/quicker on the Lee press.
Expense keeps this ol' boy from doing that, LOL. But, I shoot a LOT of .38 wadcutter now days and am thinking swapping to .38 and setting up for that load might be the thing to do with my Dillon as I don't shoot a whole heck of a lot of 9mm anymore. I'm really into my .38/.357 stuff. That load is universal accurate in all my revolvers and my go too small game load except in my Rossi rifle. I love using that Dillon, slick, not so much worry about the primer feed even though it does goof up when the little plastic fingers start wearing out. First time that happened I called Dillon and in a few days express, I had free parts and they tossed in a few other feed parts for me! Man, you just can't beat the customer service with a stick! It's worth the extra the press costs, never mind the quality of the tool, for the excellent service IMHO. I'll add another someday. I was watching Ebay until they dumped the gun related stuff. You could buy a wore out (if you can find one) square deal, send it to Dillon, and they'll refurbish under warranty. They're that good!