Reloading is . . . . well, it can become a sickness. Many of us don't know whether we reload to shoot or shoot to reload.
All kidding aside, I'd recommend against getting the Square Deal because it used proprietary Dillon dies and it only will do popular pistol calibers. You're money ahead getting a 550B and a spare primer assy so you can swap out from large to small primers in under 30 seconds with it. The 550B uses industry standard 7/8" dies and there are caliber conversion kits for almost every caliber made, both pistol and rifle. If down the road you decide to do rifle calibers, you don't have to buy a new press.
Further, when you decide upgrade to a 650 with casefeeder (a God send when processing larger quantities of brass or just because you're sick of interrupting your rhythm to pick up each case) you'll be able to use many of the parts from your 550B on your 650 such as dies, roller handle, strong mount, pickup tubes, wrenches, etc. and those you can't use, you can easily sell as a package with your 550B. Remember, it's not the most popular progressive press in the world for no reason.
Some people say that because the 550B isn't auto advance, that it's easier to learn on one. Also, it's pretty easy to use it like a single stage press as you're learning so you only have to do one step at a time to begin with. Before you get a 550B, check out this link:
Cheap Tips and Tricks For Dillon 550B and XL650s. It has some money and time savings tips and tricks to help you with your setup.