SB1911, if you're just getting started w/ shotshells, the 5th edition of Lyman's Shotshell Reloading Manual could be helpful. They have a section by the MEC staff on the 600 that might be worth your while. MEC has all manuals available online. Too, The reloading forums on Shotgun World (
Shotgunworld.com • Index page) can be a lot of help if you're having problems with it mechanically.
I don't have experience with the adjustable drop bar as I've stuck with the bushings for all of mine - I switch loads around quite a bit. I noticed you have quite a few which are worth about $5 apiece fyi. You can download a MEC bushing chart for free which will give you a starting point for most powders. Hodgdon has one for MEC bushings.
I've kept careful notes over the years on specific powder quantities and the bushings used which helps eliminate a lot of the fiddling around to get an accurate load. These days, a quick look at notes, drop in a bushing, and start loading is about all that's needed. Gotta have a scale though.
The 600 index system can come in handy when loading buckshot too by being able to jump stations easily.
Looks like a really good deal to me.