I have been happy with my Lyman ultrasonic machine. The brass cleaning solutions I have used are Lyman and Hornady. I don't see a performance difference between these two solutions. However the Hornady does not seem to store as well on the shelf. It precipitates salts in the container, and requires alot of shaking to get these back into dissolved solution, and not all of gets dissolved. The Lyman solution seems to store as-is, and no salts have precipitated to the bottom of the containers so far.
My experience is that ultrasonic cleaning does not get all the carbon film off the outside of the neck on my rifle cartridges. As others have mentioned, the brass is not perfectly shiny clean. Also not all of the primer pockets are fully clean (although many are perfectly clean). Therefore after rinsing and drying, I will run a 2nd cycle for the brass in my dry media tumbler (I use corn cob) for a final cleaning and polishing. Since the dust is a nasty contaminant (I run the tumbler outside in my garage, NOT in the house), after tumbling I wash off the dust in soap and water and place the brass on a drying rack again. Its a tedious double wash and dry cycle, but it works for me.
When you purchase ultrasonic cleaning solution for brass cartridges, be careful on the bottle labeling that it is the solution designed for brass cartridges, and NOT for steel gun parts. The brass cleaning solution is slightly acidic (but not too acidic) and will not oxidize the zinc out of the brass. You don't need to add citric acid, it already contains enough. The steel gun parts cleaning solution is slightly alkaline and does not work as well on brass. Unfortunately the packaging that Hornady uses for its solution containers is very similar between the two, and online retail sellers can mistakenly ship the wrong one to you.
