I've got the tumbler from Cabelas. I've ran thousands of rounds through it, and have had no problems. Some of the price difference might be in the size of the bowl, which would translate into how many cases you can tumble at a time. Smaller the bowl, the smaller the volume of rounds you tumble. Mine will hold around 100+ 30.06 cases fine.
I've got mine in the garage, and usually kick it off at night before I go to bed, and they are nice and clean when I wake up. I throw in a couple of glops of auto polish, which gives them a nice shine. Cabelas kit goes on sale every once in awhile, for about $52, if I remember. The miners pan that comes with it to sort out the media is all right, but I'm going to get one of those media sorters when I get the money.