I picked up one of those machines from Amazon and used it for my first run, it seems to work pretty well. After that first try I used a 5 gallon bucket and a paint mixing bit on a variable speed cordless drill. Both methods have pros and cons, but after using the drill I never went back to the machine. I could be totally wrong, but my impression was that I had a better chance of getting more trichomes off if I did it by hand.
I saw a video online of a guy who used the washing machine thing, but did not put the cannabis in the 220 zipper bag they provide. He said that he definitely had to clean the machine between runs, but that he got significantly more volume of hash from each batch by skipping the bag. I never tried that, but it sounds interesting. I followed another video and for one batch I used a boat oar to mix the buds and ice (in a 5 gallon bucket), but I think I've settled on the paint mixer.
I've probably made a dozen batches of ice/bubble hash, and the funny thing is I could be doing something wrong this whole time and I'd never know. I get great results but I have no idea how much better they could be...
(If anyone is interested in buying a used-once hash machine thing, let me know, I'd sell mine.)