The drum types may be a mite quieter. Then, there's the drawback that you have that moving part out in the open. I'm sure one of my dogs would get its ear caught in the thing, being curious.
I got a first-hand look at some Thumler stuff in a rock shop down in MS. It looks very well-made.
Also, it seems to me that you have to use water (or some other liquid) with a tumbler. Check Thumler's website; it's pretty comprehensive.