I've been a long-time organic gardener (& thus automatically a composter) for over 30 years now. Never bothered with tumblers or compost starters - totally unnecessary & really just one way for garden companies to jump on the bandwagon & make some $$. But it does/can help those folks who don't have large yards & thus don't want to go the route of a regular compost pile.
Back in NY I had 3 side-by-side bins made from discarded wooden pallets. They worked GREAT! The slats allowed for aeration, & it was easy to transfer the compost from one bin to the next. Bin 1 was for new stuff. When that started reaching semi-decompostion, it was forked over into Bin 2 to continue "cooking". Then finished compost was forked over into Bin 3 for use. Back then I was raising chickens, so my compost consisted of chicken manure & used henhouse bedding, lawn/garden scraps/clippings, & kitchen vegetable/fruit scraps. NO meat, dairy, fat/grease, or leftover cooked food unless it was completely unseasoned.
These days, now that I have 22 acres to play with here in Virginia, I compost large piles of pure horse manure (with 6 horses I have plenty to play with - lol!), & maintain a kitchen compost pile consisting of a simple welded-wire "ring" into which I layer horse manure, & garden & kitchen scraps (still maintaining the above-referenced restrictions). Every so often I just lift off the ring, move it over a few feet, & fork the original pile back over. Then move/fork back again a couple of weeks later. After a few months - voila! Finished compost.
I also do winter composting by simply depositing my horse manure & soiled bedding directly into my garden in late fall. I stop mid-winter, & by spring everything has composted down beautifully. I end up with terrific rich soil with very little work in the long run.