I keep the ends off each 1000 box of primers I finish on my 550B. Currently the stack is 40 or so tall and I have never replaced a part or done more than regular cleanup/maintenance. I load 5 different calibers and though a complete quick changeover kit is expensive, once you have gone that route you will find it well worth it.
I have run 550Bs, 650s, and the Hornady LnL,I like some things about all of them and none is perfect.
The 550B gets the nod for simplicity of use and I believe long long term reliability, also for price/value. I also think it is easiest to use when doing load development and only loading a few cases each at different specs. I have and like my case feeder as well. I can comfortably load 600 or so an hour and when I was shooting USPSA/IDPA I would sit at this press for hours on end in the winter time filling buckets with loaded ammo for the coming season.
The 650 is faster but don't even consider one without a case feeder, its just pointless. More complicated but runs like a top so does it matter to you? The priming system on the 650 is superior to the 550B in my opinion.
The LnL is well built, I just think warranty is worth something and Dillon's can not be beat. The priming system on the LnL is better than the 550B and just different than the 650. Ergonomics of a LnL without a case feeder are the worst of all three, bad enough that I would not own one without the case feeder.
For Dillon products it is tough to beat Brian Enos's website. Package deals and good advice available there. Brian Enos - Competition Shooting Books, Slide-Glide, DVDs & Reloading
The 1050 is awesome, caliber changes suck though. If money is no object then get a 1050 in each caliber you want to load for