I actually bought the tumbler to mix topsoil, compost and peat moss, and it worked great. Surprisingly stable during tumbling,and easy to retrieve the mixture.
I bought it to mix Goat Feed and it does a good job. You can only fill it half full or it is to heavy to turn. It really needs a handle to turn the drum. Other than that,,,,,,,,,,,,I really like it.
Bought one of these last year and love it, I will admit that it is a little difficult to put together, and you may have to strong arm it to get it open, just takes a good sharp yank. We did have a pretty hot summer this year and I'm sure that helped, but made great compost, and thinking about buying another one. I highly recommend this composter.