The simple answer would be it all boils down to personnel preference, and the amount of money you want to part with, some guys swear by the Lee aluminum molds, others not so much.
I have had Lees and they drop good bullets, but like all things Lee you will not get the quality of a steel mold.
Personally I like the steel molds, I have one Saeco and the rest are Lyman and RCBS, not what I would call high end, but they drop great bullets.
There are much more expensive molds on the market, but expect to dig deep.
One advantage Lee dose have over the competition, other than the price, they make a very cheap push threw bullet sizer, as well as a bullet design made for Tumble lubing which is also very cheap to start out with.
As to what Bullet lube dose and dose not do, you will get several opinions, my best advise here would be, buy the Lyman cast bullet manual, if thinking about casting it is invaluable.