I have been using a Dillon 550B for all of my pistol cartridges for about 8 years now about 100,000 or so rounds combined. I reload .45 acp, .357 magnum, 9mm, .44 magnum on it and I have tool heads set up for all of the calibers.
I only own 1 dillon powder measure ONE. I have no problem switching it from one tool head to another, I also have no problem adjusting it, it takes about two minutes to adjust the charge weight when I switch calibers..
I do all of my reloading of rifle calibers, and any specialized seating of non standard pistol bullets on a Rock Chucker IV. The Dillon runs trouble free, it has its original parts, although I have a spare parts pack I have never replaced a single broken part on my 550.
I also haven't needed a milling machine to adjust the dies, or a wooden dowel to track my primer level. I mostly load cast lead bullets so I appreciate the seperate crimping die. The powder measure on the Dillon shines on its consistency for low charge weights used in pistol calibers. I compare it to my Lyman measure, and my Redding Benchrest measure (both rotating drum designs), they are good for rifle but stink compared to the dillon for small pistol charges under 10 grains. My Dillon measure does not leak powder.
I thought about a Hornady LNL, but the expense of converting is too great since I will need completely new dies or a milling machine and tooling that can cut carbide.
I have also compared the cost of caliber conversions without a powder measure in each one,
Its the same.
A gent who is a high volume reloader at my club, he assembles components for other shooters as well as himself, and does 100,000+ .45 acp per year, switched from two STAR machines to a LNL a couple years ago. He had many problems with parts breaking and the press jamming in a high volume usage role he also found the seating and crimping with the Hornady dies to be inconsistent and problematic due to the fact that he uses cast bullets lubed with alox.
He sold the LNL and went to a Dillon 650, and the problems went away.