Not familiar with the Challenger kit, but I started out with the Anniversary kit about 15 years ago. The Challenger vs the Anniversary kit looks like the only difference is the "breech locking" die insertion vs the old fashioned screw in method. If you are reloading for "common" rounds this kit will do fine to let you find out if you want to go deeper. If you want to re-form brass dramatically, you would be better off (IMHO) to go with a "higher dollar" press (RCBS, Lyman, Redding, Forster & etc) only because of the force required for reforming. The Lee scale is adequate (but that is the first thing I got a better one), the powder measure works OK and I stil use mine a fair bit. The one thing I would get that is not in the kit is the Lee Ram-prime - about $10 to $15 - as (again, IMHO) the hand primer in the kit did not give me the "feel" I wanted when seating primers. Might want to get a case trimmer, too.
There are a lot of reloaders who started out with Lee equipment and either stopped reloading entirely because they didn't like it or went the opposite direction (my hand is up) and started reloading for everything they have and began to acquire "better" equipment as the need arose. There will always be something "better" out there that you think you have to have, but you can do most anything you want with a good 'ol Lee single stage press and unless you abuse it, it will last a long time.
Oh, yeah, get a good reloading book, I have the Lyman, but there are others out there. They will walk you through most every step of the operation in plain, understandable language.
