Let me start by saying that I don't want to offend anyone and if anyone is offended, it is not intentional. I'm saying this because some take criticism of their equipment personally.
I've loaded on lots of different presses. I started out on the Lee 1000, then Loadmaster, been through the LNL and I believe every model in Dillon's line. I'd put this thing about auto indexing being an issue out of my mind. It isn't an issue at all and having it doesn't make you go any faster. In fact, on those occassions when things get screwed up, auto indexing is more of a PITA than it's worth.
If you have a really tight budget, the Lee's will work. They will get the job done, but WILL require occassional (or more than just occassional) tinkering to keep them working right. I really don't think that I know of anyone that regretted upgrading from a Lee to a Hornady or Dillon and I don't think that I know of anyone that went from a Hornady or Dillon to a Lee because they thought the Lee was a better machine. Those that have never loaded on anything other than a Lee, just don't know how much better it can be.
That having been said, I'd have to give the Dillon 550b a vote. The 550 is like using four single stage presses at once. It's operation is that simple. To index, you just flick the little handle on the shell plate with your thumb. Maintenance is very simple and is pretty much limited to just cleaning and lubing the press from time to time. Caliber changes are quick and less expensive than they are for the 650. I know a lot of people that love their 650, when they are working right. They are more sensitive to being kept clean and there is more to go wrong than on a 550, so there is more maintenance. Caliber change kits are also a lot more expensive. The one real advantage that the 650 had over the 550 was that you could add a case feeder to the 650. You can now add that to the 550 also, so it's a moot point.
The Square Deal B is a very tempting setup, due to price; but, I'd steer clear of it. It just doesn't have the mass or leverage of the bigger presses and just seating primers can get to be a chore. The press is small with a very limited amount of work space. Loading on it just feels cramped. Another downside is that the dies are proprietary. You HAVE to use the Dillon SDB dies with it. Some might not mind that, but there are some die sets that I prefer to have from another manufacturer, like for .45.
The Hornady LNL is a nice press. I just never warmed up to it. I was never crazy about auto indexing. Like I said, it can be more of a PITA than it's worth.
I'd say go for a 550b. The only reason that I'd consider going with a 650 is for the extra die station, if you think you'd use it for maybe a powder check setup or something. The auto indexing doesn't even factor in.
The only press that I still have is my 550b and in the last month I've loaded about 8K rounds on it in three different calibers. I doubt that anyone using a Lee 1000 or Loadmaster can say that they loaded 8K rounds without having to fiddle with the machine at least once.
As for many years to come, I bought my 550b in 1997 and the only thing that I've had to change on it is the spring in the primer seater cup. The spare parts bag or kit that I bought when I first got the press is still sealed and I don't even know what dealing with Dillon is like because I've never had to, although I've heard that their customer service is excellent.
