I'm not sure how hidden they are, but there are costs. If 9 mm is the only chambering you will load this way, the Dillon Square deal is a good machine that comes already set up, so adjusting the seating die for your bullets and the powder measure to throw your charges are all you need to do to get started. However, it uses special non-standard compact dies, so if you want to change the caliber, you have to buy Dillon's dies along with the different powder actuator/flaring tube and the different shell holder plate and buttons. As a result, a caliber conversion kit is $100. Also, the press throat and special dies limit it to handgun and straight-wall carbine cartridges.
The Dillon 550C is about $50 more than the Square Deal if you buy it with a caliber conversion, but no dies (so you have to set it up). It can be bought with no caliber conversion for about what the Square Deal Costs if you already own some conversions and just want to keep a second press set up and ready to go. You have to index the 550C's rotary shell holder with your thumb rather than it indexing automatically, as the Square Deal does, but it uses standard dies, so they standard conversion kit does not include dies and, as a result, costs $53. The 550C throat is big enough to accommodate most rifle cartridges up to the 460 Weatherby, so you can load almost anything on it that uses standard dies. It has removable tool heads so you can buy extra ones to be able to leave your dies set up on them, and then only have to change the shell plate and retaining buttons for a different size case head.
Personally, I like the manual indexing of the 550C because you can raise and lower the ram and check everything without the shell plate moving or an indexing pawl jamming you up. You usually don't need that unless something doesn't feel right. But when that happens—say, a primer doesn't feel like it seated normally—the ability to operate the ram and remove the case retaining button and slip the case out to check it before the powder is dropped in is a plus. It also means you can use it like a single-stage press when you need to. I've used mine with a bullet puller in that fashion. Mainly, you control the pace entirely by the speed of your efforts, making it is a good choice for a first-time progressive user.
I have a Square Deal dedicated to 45 Auto that I got in the late '80s, and it has worked well. With me loading cases and primers from pre-filled primer tubes and operating the handle and my wife feeding bullets for me, we once turned out 250 rounds of 45 Auto for a match I was late to in about 12½ minutes on the Square Deal. I think the 550C would have got up to about the same speed if I'd had one then, and she was also advancing the indexer.
DISCLAIMER: I am not recommending you marry just to have a bullet feeder or indexer, though if you are looking for that one last reason to push you over the top…
Other brands include the Lee you mentioned. Many people like it, but also say you need to be prepared to spend time tweaking it and that your tweaks work loose after a few hundred rounds, cutting down the overall production speed. But I don't have personal experience with anything but their old progressive shotshell loader, so I can't speak to the new machine.
Others prefer the Hornady LNL machine. It has five stations instead of four, which I like the idea of, since that will let you install a lockout die or other powder check die to make sure you don't get an empty or an over-charged case in it. Others like the RCBS machines. Others like the old Star machines and rebuilt ones are available from Star Machine's new owner. But I don't own any of those, so I can't speak about them adequately.
There are bigger and more expensive Dillons, but I wouldn't start out that way.
