Sounds like you may just be frustrated. Not knowing what press you are currently working with or exact problems you are having, I can't be of much help other than to say they both can be made to load ammo without making you kick a cat or cuss your wife.
On both machines you can (and should) run just one case at a time to help setting up/figuring out each station, one at a time.
The spring retainer on the LNL allows removal of the case at any time, on the 550 you can take out the buttons to accomplish the same thing.
Again, just set one station at a time, exactly the same as your SS press and the only difference will be when you setup the powder measure.
If you have any specifics on your 550 primer issue post them, I bet there are more than a few of use that have already had the same problems.
If you hurry you can also get on the phone with a Dillon tech and they will walk you through it.