It works well, but you need a lot more polishing media than what is included. You should fill it 50-60% full, so count on buying 2 kg steel shot.
It is a bit fast for dry media, walnut tends to not tumble but go flying a bit. You want the media to ride up the side of the barrel and then slide down to the bottom. Filling 50-60% gives the longest “sliding hill”. If the parts fly and hit each other they will dent, so a tumbling/sliding action is what you want.
You can put smaller drive wheels on it to slow it down. I have a lathe so I turned them down.
There is still enough speed when you load it up with heavy steel shot.
If you tumble delicate or rare items such as coins you might have to tumble only one item at a time to avoid all possible damage by parts hitting each other.
All in all a very good buy for the money.
Jonathan Rönnow-Nielsen 
