I bought this with an open mind, thinking it might save me time on the job. It doesn't. I've tested it with a dozen different types of brushes, with different cleaning agents, and it didn't work. Yes, it cleaned some of the paint out each time you used it, but I could get more paint out in 5 seconds without it. I gave it a really long test on one particular brush and one of the more expensive cleaning agents you can buy, I put it through 20 cycles (it says it will clean in about 3 cycles) it cleaned out about 80% of the paint, then didn't clean out any more. I took to cleaning it manually, and after 5 minutes the brush was completely clean.
Don't waste your money on this, and the batteries you'll have to buy. Spend your money on decent professional paint brushes with easy-to-clean filaments - like the Wooster FTP or the Proform Picasso, and clean them the good-old-fashioned way... which works!
PS. I could have sold my Brush Doctor, or given it away. But I'm an ethical person and it would have been underhand of me to give or sell someone something that was rubbish. I threw it in the bin, where it belongs.