GW,
I think the biggest difference there is I've owned and used both. There's are some things that stand out for me:
The biggest difference is we are different people with different likes.
1. With the LnL bushings, you don't get the die plate/tool head "slop." By that I mean the toolheads/die plates tend to move during press operation, because they have a certain amount of built in tolerances to allow for moving the toolhead/die plate in and out of the press. The Hornady LnL bushings twist in and out and "lock" in place, giving you a much more positive location for your dies. Much more like a single stage.
Dave, I like the slop. It makes things line up so I don't pull case out of align. 40 years ago I was taught by the "masters" at Handloader Magazine to "create" slop in Rock Chucker shell holders for the same purpose. It was simple really, you just loosen the spring holding the shell holder to the ram, so that it just holds...barely. I know you think Hornady does alignment best....I just don't agree. Depends how you use the press. Too fast with the handle makes less straight ammo with the Pro 2000 or the Dillons. With the Hornady you are totally dependent on Hornady for a perfect casting. You of all people know how fast that can go south. Judging from the many Hornady posts I've read over the last 3 years, Hornady isn't immune, nor do they outshine the other manufacturers in that dept.
2. The flexibility of the the LnL bushings is much higher than with the toolhead/die plate. If you're loading using a FL sizing die, you can instantly replace the FL sizing die with a completely adjusted, ready to use, Neck sizing die instantly. This is very convenient and I've missed this capability very much since I sold my LnL.
"Much higher".........maybe a little higher maybe 40 seconds. All my dies are pre-adjusted too, you just have to unscrew and rescrew.....but since I NEVER use neck sizers I don't care. Again the difference is in the humans.
3. Convenience of storage. I stored my dies with LnL bushings installed in an MTM case, which held four sets of dies at a time. Two of these boxes held most all the common caliber dies I had. A third held the rest. One can also use the Hornady die boxes to store the dies with the die bushings. Other brands of boxes sort of fit, but are tight.
Again different humans. I store may die heads in clear soft plastic index boxes, lined up neatly on their own 8" high x *" deep shelf at sitting eye level. Each die head has not only the normal dies mounted (preadjusted), but in the case of pistol dies, a bullet feeder die, and a Uniflow Powder through expander. In my mind (my mind) there's nothing faster or simpler.
We are just going to have to agree to disagree. Thankfully in this country we can.....so far.
Evidentally RCBS safe capacity may have changed. They now offer a larger capacity Uniflow for "large calibers." I suspect all of the "safe" capacity jargon may be slang for: "We designed it with this capacity, have thousands of these reservoirs in manufacture at the present and really don't want to change."
I suspect if enough pressure is put on the manufacturers, they will increase the capacity. That said, the Hornady and Dillon measures seem more designed for progressives, while the current Uniflow was designed for a single stage. RCBS has recently added a very large capacity powder measure for "large calibers" I called and got them to send me a couple of the reservoirs.
They are huge, bigger than either the Dillon or Hornady reservoirs. Unfortunately, they don't fit a standard Uniflow. But they do show RCBS can provide larger capacity reservoirs if they choose to.