I have the Hornady and I'm very happy with it.
Of course I'm the kind of guy who thinks the grass is always greener on the other side so I may buy a 650 to give it a whirl.
I'll give you the negatives of the Hornady and you can decide for yourself.
I'll give you the negatives I've heard of the Dillon but most Dillon owners swear that there are no negatives.
On the Hornady primer seating is finicky.
Hornady has revised the primer punches so that powder can no longer get jammed under them.
Some people are shimming the arbors due to different tolerances.
There is an active thread on this somewhere here.
This seems to help with case tilt.
Powder measure swaps. The powder measure needs to be swapped over to go from a pistol to a rifle rotor and vice versa.
This takes several minutes to do. If you are using powder through expanders you will need to buy separate case activated lower assemblies at $25.00 a pop. Add to that $20.00 for 5 bushings and you're up to $45 per caliber change and you still need to swap the powder measure over.
The case feeder for the Hornady is more expensive than the Dillon but the plates for small rifle, large rifle, small pistol, large pistol are twice the price for the Dillon.
One of the negatives of the Dillon 650 is that it will spit out a primer regardless if a case is present or not.
This means you must retrieve the errant primer.
The Hornady will only deliver a primer if there is a case present otherwise the primer will return to its position waiting for the next case.
The only thing I can say about the Hornady is that the case feeding could be a little better but it's not that bad with a few homemade mods found on the boards.
I don't regret getting the LNL and it has put out tens of thousands of rounds so far.
If I had one of each I could be totally objective.