I have used the Rock Chucker for years. Great press in every respect *except* handling spent rimers. They go all over the place. I have used every type of primer cup/catcher available from RCBS, and I might as well let the primers hit the floor instead of trying to utilize the primer catchers - they work at best about 60%.
A good shooting buddy of mine bought a LNL AP from Cabelas about a month ago, and seems to like it. I have a mixed reaction to it. The LNL die removal feature is ok, but to swap tool heads on a 550/650 is MUCH easier and less hassle.
The primer system leaves something to be desired in my opinion. The auto index, I can take or leave, the cost vs. a 550 is almost identical when getting everything setup equally. A 650 will set you back a bit more if you include the powered case feeder and all the case feed plates.
I have loaded a few rounds on his LNL, it is pretty smooth. The fit and function seem to be robust. I don't buy Hornady presses any more since the days of my owning a ProJector. Some parts are no longer available, so I was out of luck when I needed a couple of replacement parts.
Hornady's customer service may be great *now* but that is a result of pressure from Dillon being so helpful and supportive to their customers.
Some of you may have loaded long enough to remember the days when Hornady had a one year guarantee and a long price list of replacement parts in the owners manuals. Dillon has had their no BS warranty since as long as I can remember.
Dillon will do a refurb on their products for a nominal fee (or free if you have a problem that they deem serious enough to replace the press entirely). Hornady doesn't offer anything similar, as far as I know.
Many, many people buy used Dillon's on EBay and drop $29.95 to send it to Dillon for a complete factory rebuild. The $29.95 basically covers return shipping and packaging. If you require repair that isn't usually a user repairable part, they pick up the freight both ways and all the parts.
From a standpoint of economy, I would buy a used Dillon amd get a factory rebuild done on it. Hornady LNL (or any others) don't hold their value like a Dillon does. The result is, if you decide to move to a different press in the future, you most likely won't lose (much) money.
The LNL is a great idea, a fantastic upgrade from previous Hornady products and according to many, worthy of some consideration.
From my standpoint, owning a Dillon is great, because the product is outstanding, the price is reasonable and YEARS of proven track record and customer service speak for itself.
My buddy with the LNL loaded a few rounds on one of my 550's over the weekend. His only comment was the 550 felt 'smoother'. Who knows, maybe it is, maybe not.
I can recommend that if you decide to buy the Rock Chucker, the LNL inserts (?) are available stand as a stand alone item. They would definitely be an improvement over swapping and readjusting dies every time.
Buy the Rock Chucker ? Definitely, you can still find many uses for it when you decide to go to a progressive.
Buy a Hornady LNL ? No, I don't think so.
Just my opinion, worth every cent you're paying for it - zero