I'll start by saying that I have a Dillon XL650, but I
learned reloading on a neighbor's Dillon RL550.
It's a good press, but the one thing about it that irritated me to no end was the priming system: if you didn't keep the little reciprocating arm that feeds the primers absolutely clean, it would skip primers. You'd have to stop and clean out the arm, then clean all the powder out that got all over the place. If you kept it free of powder in the primer area, this was a non-issue, but even a few grains could jam up theworks, and the primers would not feed into the priming arm.
This is one of the big reasons I invested in the XL650 - the primer magazine system works almost flawlessly, even when some crap makes its way into the priming station. It uses a cylindircal magazine (looks like a flattened revolver cylinder) instead of the reciprocating arm. It's all difference in the world, but it's also all the world of difference in price for the press and all of the options - my setup (including electric case feeder, digital scale, large media tumbler, aluminum roller handle, strong mount, blah, balh, blah...and all the trimmings) cost me right around $1,100
You can get into a RL550 for a little over half that.
I have no experience or words for you on the Hornady press, but an old Lieutenant Colonel I used to work with LOVED his RCBS rockchucker and would never have it any other way.