Heck yeah it works!! I have nothing but good things to say about the ultrasonic cleaner route. Inside of those cases are CLEAN.
First time I did it I was very pleased and dissapointed at the same time - it took abut 30 minutes to get them clean, but in looking back on it the issue was that the cases were all 6X fired - there was a LOT of crud in there. Second issue was that I was not using enough soap. Use more - big, long squirt. On brass that has been shot a lot the water will come out black.
My formula has been one hell of a big squirt of concentrated soap and a 30-30 case full of Lemishine (get it from Wal Mart). I make sure that every case is full of water (no air pockets), I notice where there is the cases do not clean nearly as well or as fast. I also turn the heater on in the cleaner - hot soapy water.
After they are done the first time I usually roll up a paper towel and twist it around each one to make sure all of the crud is off. This is just me, probably way to OCD - and for me case prep is a great way to zone out and decompress for a while. But also, if I am going to go through this trouble, might as well be perfect.
Once I am done with that I throw them into my vibratory cleaner, just to get rid of the water and clean it up some (add some shine) and remove any residue (there isn't any really with my way, but some also rinse them in hot water after it is done). Again, way too OCD and not needed, but it is what I do. But when when I follow this procedure, WOW, new brass. Inside is reflective.
When I first did this the inside was clean enough I could see flashole burrs that I missed originally, and I also had extremely clean case mouths in inside necks. Once I ran 0000 steel wool inside the necks the bullets went in great.
Like I said, first time takes a while, after that if you keep them clean after every firing you are at about 5 mins, max, depending on how much brass you throw in.
I got my ultrasonic cleaner at Harbor Freight, $50. Works great, no problems. What is also nice about it is that I got one big enough to throw my bolt in and clean it (not with water), and not worry about getting "way in there".
Good process and well worth the money IMHO. Wouldn't go back.
Hope this helps.