"Anyone else use a tumbler not made by a reloading mfg?"
I don't think any reloading mfg makes a tumbler. They all get them made by others to the marketers specifications and color! From the way they look to me there must be three providers in the business.
If yours has no power switch, put a simple power cord switch on it.
Cooling is a major problem with many viberator tumblers. I drilled a series of 1/2" holes around the base of mine, on about 1 1/4" centers. It now runs cooler and the second motor has lasted a LOOONG time! If your's does burn out go to an electric supply store and get a cheap repacement motor for a bath ventalation fan and use it, they are pretty much the same things and work quite well in a tumbler. I took my bad motor and the clerk searched until he found one that had mounting holes in the same places. I don't think any reloading tumbler has a ball-bearing motor, just simple bronze bushing type bearings.
The oil in the motors will eventually dry out and keep the shaft from turning, that will burn the motor windings out pretty fast. If you ever hear a change or sense any dragging of the motor when it starts, turn it off and take it apart far enough to allow you to put a few drops of good oil on the bearings, NOT WD-40! That's some good stuff for water displacement but it gums too badly for guns or moving machinery, use Automatic Transmission Fluid instead. ATF is a good light lube and is non-gumming. (Use it as a gun oil too, it's really great stuff!)
There is much too much agonising over choosing cob or nut case cleaning media. Actually, both work and there is little difference between them. Just run the tumbler long enough and you will get good cleaning. I sometimes run mine over night! Both media types are available at low cost from larger pet supply stores. Add a little bit of auto polish to get a better shine if that's what turns you on.
You can soak dark, tarnished brass in a 50:50 mix of vinegar and water for a few hours, at least until the tarnish turns pinkish, and then tumble normally for a normal appearance.