Buying a new composter. How are the dual bin tumblers compared to the "standard" bins that sit on the ground? I would think that the "standard" bins would be better due to the benefit of having access by worms. Feedback please?

I prefer the stand alone bin. I had a collapsible wire bin that I loved. Plenty of air. The sides could be disconnected to let me rake out the compost. When I moved to a condo and downsized, I just use a big black pot that a tree came in - with drain holes at the bottom. I often find nurseries of wrigglers in it - a win-win for my garden and the worms. I never even turn my compost much - that takes a bit longer to compost, but I still have good compost every spring. One thing people forget - you can empty the contents of your vacuum sweeper into your bin - it's full of good stuff.

I haven't owned a tumbler but my sister has. Even the smaller one she has now is so hard to turn, looks about like this one
https://www.google.com/url?sa=...

And if you are going to do any quantity of tree leaves, you'll fill that one in a day.

I have composted for decades in wood or plastic bins on ground. Worm access isn't a huge factor in my opinion. Worms don't eat tree leaves.

What is your general location/climate? What kind and amount of stuff will you compost?

Go with the stand alone, much more volume. I've had 4 of them for 15+ years, work great. Know a few people that have the tumblers, they all have got rid of them, they don't make enough compost

I bought my mother a rubberish portable bin. It makes a 3' diameter bin with a lot of air holes, black in color, collapsible and comes apart. Basically you set up the bin, fill it, and when the bin needs turned or emptied, you take the bin connectors off, remove the bin, place the bin in a new area and then flip the pile back in to the bin.

I made my own bins. Three 4x4' cubes out of 4x4 posts and plastic coated fencing. Have lasted me 20 years.

I have a hard plastic sided that sits on the ground model, but not very good, Not sure what type of space you have for a composter, but i have built a large double bin composter out of pallets, 4ft X 8ft by 4 feet high, you can go smaller and just a 4x4, again using pallets, it was very simple to build, I pull compost from the bottom and fill from the top, I compost everything i can, collect leaves and use kitchen scraps, grass, shredded paper etc. we save kitchen scraps all winter,it freezes outside and come the spring dump it in the bins. Composting can be very simple (If it stinks its too wet, if its not working its too dry or needs aerating) or as complex as you want it to be. hope this helps, once you start getting that rich black soil mix(compost) keeping the bins full can become an obsession!