I found that by charging a case and immediately inspecting the charge height and seating a bullet, I eliminated squibs from my process. I just HATED loading blocks.
However, when the first 5-station progressive came out that was affordable (the Hornady Pro-7, I think), I immediately bought one and retired my single-stage presses.
Never regretted buting the Hornady--always worked great for me and, until the L-N-L came out, I had been able to have Horandy upgrade me for very little money.
IF you want a progressive, get a press with at least 5 stations--unless you are only loading bottleneck cartridges. Also, for most of us, an auto-index makes it very hard to produce a double charge. No insult, but the 550B owners I know are all very OCD and controlling. EVERYTHING must be under their control and nothing happens unless they MAKE it happen. Some even go so far as to ONLY load one case at a time so they can always keep an eye on what is happening.
Conversely, the one SDB owner I know only loads to plink and is happy with just the same-old same-old and hates any change whatsoever. Have a feeling, from magazine articles, that most SDB presses are set-up pretty much once and nothing ever changes.
I personally "love" only two progressive presses: the Hornady L-N-L AP and the Dillon Super 1050. I want a station for an RCBS Lock-out die or, I want to be able to separate case expansion/mouth flaring from powder charging at times, and need 5 stations since I am NOT going to seat and crimp in one operation.
IF you consider the 550 or the 650, you HAVE to get a case feeder. The Dillons are very non-ergonomic and you need to feed a case into the right side of the shell plate (either one at a time or you manually load a tube with 25-30 cases) and, if you load sitting down, you will be hopping up and down all the time. IF you don't want a case feeder, get the Hornady. If you WANT a case feeder, get the 650. The backwards ergonomics are fine as long as you have a case feeder on your Dillon.
With the Hornady, I simply had always picked up a bullet and case while I cycled the ram. When the ram was down, I fed a case into the shellplate and placed a bullet on the charged case as I inspected it (unlike the Dillon, the charged case is right under your nose and you have to work NOT to look into the case as you place a bullet on it) and never saw any need to spend hundreds of dollars on a case feeder.
Then, I used a friends new 650. He was so proud of it. All the guys at the club had told to buy one and he knew he was better than the Hornady I told him I used. After we loaded about 100 rounds, he went into work the next day and ordered a case feeder. I made sure never to say anything despairing about his press, but I sure learned that I wouldn't own the sucker WITHOUT a case feeder.
If you want to go out and crank out 100 rounds in just a few minutes, get the Super 1050. I used to have one in the garage and I would spend about 10 minutes out there and have a week's worth of .45ACPs loaded.
