First, I'm no fan of Harbor Freight. It's made-in-China junk - I've bought heat shrink tubing from there that didn't work. HOWEVER, I did decide to try the Chicago Electric Ultrasonic cleaner for two reasons: 1. I wasn't sure I would like ultrasonic cleaning or if it would be worth the trouble and 2. It was cheap so if it didn't work I wouldn't be too upset.
I read the tech article on here about ultrasonic cleaning, so I bought the 2.5 liter cleaner when it was on sale for $59. I couldn't source any science beakers locally and I didn't want to order them online so I looked around and eventually found some candle holders at a craft store the size of beakers that I figured would work just the same, albeit a little more fragile.
I didn't want to get into the multi-step clean/baking soda/vinegar/whatever so I tried a couple of different cleaners. I found one that works like a champ: Krud Kutter, sold at Lowe's. It's clear, non-toxic, biodegradable, and smells good, so I figured if it didn't work on my brass I could wash the patio furniture with it. ;D
I'm happy to report that I've been using the cleaner, my candle "beakers", Krud Kutter, and I've been tickled pink.
On my very first attempt I played by all the rules in the article: stood the cases up, 15-20 per beaker, 3 480 second cycles, etc. I cleaned some once-fired cases that way and they came out looking brand new so I didn't do anything else. After doing a few batches (roughly 100 cases) that way I found that there was still some crusties in the primer pockets.
The only downside to ultrasonic cleaning that I've found is that the cases take a while to dry. I dried some in the oven on a cookie sheet once but found my wife didn't get all of the grease off of the cookie sheet so I ended up tumbling them afterward. Huge mistake. The tumbler was fine but picking the walnut shells out of the primer pockets reminded me why I came to love ultrasonic cleaning. I bought a brand new cookie sheet, then after a couple of batches I discovered that drying them on 200 degrees causes the brass to tarnish. That's no good either 'cause everyone knows pretty brass shoots better ;D. (I have a modern oven with no pilot light so that's not an option.)
I also discovered that using warm water is better than using the ultrasonic heater. The heater in the cleaner not only heats up the water but gets hot enough to leave stains on the cases. Warm water works just fine.
My current method is to lay them down on their sides, about 15-20 per beaker then fill the water/soap mixture to be level with the water-line in the cleaner; use warm water; run them three 480 second cycles on the cleaner; rinse in cold water; and air dry them for 2-3 days. While drying I stand them up on shop towels. After the first day I pick them up and blow any remaining water out of the primer pockets otherwise they won't completely dry. I found that laying them down ensures the primer pockets get cleaned too. If they're standing up the heads absorb more energy and don't let the crusty stuff come out of the primer pockets as well.
Lastly, the thing makes a really high-pitched whine that irritates my ears so I wear muffs when working around it or leave the room while it's running.
I've done about 1000 rounds this way and they always come out squeaky clean. The cheapo harbor freight cleaner is holding up quite well so far, and I've been very happy with it for $59.
Good luck!