Benefits of Rotary Tumblers

* Easier to use

* Can start them and forget about them

* Usually less expensive to buy

* Gets rocks rounder

Benefits of Vibratory Tumblers

* Can put a nicer shine on rocks

* Polishes rocks quicker

* Does minimal shaping of rocks

* Handles fragile rocks better

* Uses less grit and polish

Disadvantages of Vibratory Tumblers

* Tend to be noiser

* Have to check them at least daily
* Does not get rocks very round

* Hard to get the right proportion of grit to water, especially in the coarser grits

I prefer to start out in my rotary tumblers to get the rocks rounded, and then transfer to a vibratory tumbler for the last stage of polishing.

Vibratory tumblers really outperform rotary tumblers in polishing difficult stones like obsidian, glass, or common opal.

A tumbler designed for polishing brass shell casings, jewelry, or parts will generally not be appropriate for polishing stones. Deburring tumblers are generally not suitable for rock tumbling. If there is any question, ask the seller before bidding.

A rubber tumble barrel will last longer and operate quieter than a hard plastic barrel.

The Chicago brand tumbler which is commonly listed as a low priced model on eBay tends to have a weak drive belt, so it's a good idea to get a high quality replacement belt at the same time as you get the tumbler. Other than that my Chicago tumblers have been very reliable.

You should get a grit and polish kit with your tumbler.