It's my PERSONAL OPINION Dillion machines are for people that are serious.
I'm like most people, I tried other machines, but as volume went up the glitches and limitations showed up and got real annoying.
If you leave the machine sit for a year at a time, probably not worth tooling up a Dillon.
If you use it a lot, that spare parts kit and extras are worth gold.
Dillon IS a mass produced machine, it will need tuning, a few gadgets as you get rolling faster & faster, but it WILL keep up with muscle power with very little work. My XL650s ran out of the box, ran a lot better with a day of tuning.
Let's face it, at 350 an hour it will keep up with just tuning, get up to the advertised 600-650 and hour, and you will be experienced enough to identify glitches and fix them.
As for dies & other accessories, most won't work or won't work well.
The dies interchange, but many won't run all that well, sticking issues, small mouth/misalignment issues, etc.
I don't consider dies sacred, so I modify to work where I need them.
A little trim here, a little polish there and most can be made to run mostly trouble free.
*IF* I could go back in time, I would have jumped from the first Lee 'Turret' right to a Dillon 650, would have saved a crap load of time & money on other progressives that simply can't be made or kept reliable with thousands of rounds a month.
With Dillon, cleaning & lubrication! Keep it lubed.
I clean anytime it stops, a quick pass with the vacuum nozzle, a little brush here & there and you will avoid full tear down & cleaning for a year at a time.
I lube every couple thousand rounds (if you miss one it's no big deal), a little lube at several intervals is much better than a lot of lube at the start.
The aftermarket supports the 650 pretty good, lots of little upgrades. Rollers in friction applications, adjustable parts where Dillion didn't put one in for adjusting to the Nth degree, some of it works, some of it doesn't, some is just silly...
When you get rolling, the 'Extras' come in REAL handy!
Extra primer tubes in particular, spare parts for when you break or loose those little SOBs,
EVERYONE gets it rolling, then tried to see how many they can load, and it WILL load everything in the house! Once it runs smooth, it's addictive!
There are motor kits out there, I went with a motor on a 650, but I personally think the frame isn't strong enough, and the machine doesn't run on roller bearing, so I stopped when I noticed excessive wear.
Now, if you talk Super 1050....