I'm currently on stage one of my first 3 lb. Mix of stones. Peeked in at my 1 pound quartz rock and it's looking fine. The little rubber thingy on bottom side (1 on each corner); the one near motor, the adhesive melted off and the thing won't stay attached.
[R&T Reply: Hi Michael, is it the "foot" that came off? (The rubber feet help prevent vibrational noise and/or scratching on the surface that you place the tumbler on.) I'm sorry to hear that; I think it might be a problem that happens more often when we ship in the summer. You can replace those with the little adhesive dots that are sometimes available in grocery stores, in the housewares section, or sometimes in furniture, craft or hardware stores.]