Without the bullet feeder or case feeder, the speeds obtainable between the 550, 650 or the Hornady L-N-L are probably comparable.
Of course, with the bullet and case feeders, the 650 and the Hornady are a bit more difficult to change over to other calibers.
I load primarily handgun cartridges on the progressive and spend about as much time setting up, then packaging ammo and cleaning up as I do stroking the handle on the press. Even with tool heads or L-N-L bushings for each cartridge, I probably don't save too much time on a cartridge change, but it is more fun than threading the dies in and out!
But, for handgun cartridges, I like the reduction in case handling since handgun cartridges requires extra steps over bottle neck cartridges.
I recently bought a Dillon SDB press set up for 9x19 to play with along with a cartridge change for 45 ACP. I have not gotten the press on line yet and am already considering buying a second to keep set up for 45 ACP. Virtually no cartridge change time. With the SDB, the entire press set up is only about $120 more expensive than a complete cartridge change kit.
I still prefer to do rifle cartridges on the single stage. The runs are smaller, I make load changes more frequently, and I prefer the powder charge control with the powder measure separate from the press. I can load 100 rounds on the single stage faster than fooling with the progressive.