Michael,
I got one a couple of years ago after a visit to Abe Chabers shop. I heard a noise in his back room, a low buzz, I asked and was shown the little tank at work. Abe then cleaned a Highwall action I had disassembled and I was amazed that the internal parts came back with most of their original finish intact, vivid case colors and bright nitre blues.
The major manufacturer in the US is L&R from NJ. They make the units that Brownells sells, indeed they sell the same unit under many names. They sell a lot of this size to denists and tattoo artists.
I first bought an unheated 140 size and it worked well but then I was able to find a heated 210 size and that's large enough for a pistol frame. The heated ones work very well.
I use Abe's recommended mixture of water, Simple Green and non sudsing ammonia. When I got the heated one I immediately tore down a grimy Rem. M14 I had gotten for free and cleaned every part, they came out looking like the day they left the factory. I was even able to clean the frame with barrel attached, one half at a time. Now I have to figure out how to get the thing back together, gun in a box!
Brett, interestingly enough last week I tried to clean some old brass 12ga shells, it did not work well, I may have to find a different solution, maybe I'll try Michaels.
By keeping a watch on eBay you should be able to find a good condition, used, heated 210 for about $300. A quick test to see if it's working is to fill the tank with water and suspend a piece of aluminum foil in it. In a few minutes the foil with start to show holes and eventually disintegrate.
BTW, they are great for cleaning the crud off saltwater fishing reels.
Caveat! These cleaners remove every trace of oil and the parts will start to rust right away. You can get an extra pan to fill with oil and then use the ultrasonic action to lube the cleaned parts.
Here are some pics of the internal surfaces from that 1885 after cleaning.
