Ultrasonics work well, but can be over-kill on guns that aren't allowed to get so filthy that you need to either do a full disassembly or use an ultrasonic.
Much depends on what cleaner solution you use, noting that some cleaners can damage gun parts and will do so faster in the tank.
As example, Simply Green and some other "super" degreaser soaps will attack aluminum and can do serious damage quickly.
Some solutions may attack plastics and some gun finishes.
Ultrasonics will eventually remove any painted markings or sight paint as used in 3-dot sights, and if you use a solvent that attacks paints, the markings can be removed almost instantly in the cleaner.
Ultrasonics will not remove copper fouling unless you use a solvent that normally removes it, and it won't remove heavy leading or carbon fouling without some help.
If you use a water-based cleaner, you have to rinse it out, dry, then get rust preventing lubricant into all areas to prevent internal rusting.
If you use a solvent-based cleaner you also have to dry and lube carefully.
Remember, that ultrasonics will remove ALL lubricant from ALL areas, even the tiny crevices no other cleaning method can get to.
Happily, most gun lubricants creep and will infiltrate into most areas.
A hair dryer makes a great dryer. Note, hair dryer, not heat gun or torch.
It's expensive, but an excellent cleaner solution is a bucket of Dunk-Kit from Cylinder & Slide Shop.
This is a bucket of a cleaner-lubricant that intended to clean and lube the gun by simply soaking it in the bucket.
It works well as an ultrasonic solution because it not only cleans, it leaves a thin layer of rust preventing lube on all surfaces.
I'd still recommend applying a thicker lube to critical parts.
This lasts a long time and the fouling sinks to the bottom of the bucket although you can strain the fouling out before returning it to the bucket.
In short, the ultrasonic is best as an occasional total clean method, not an every time cleaner.
Pointers:
Use a basket or wires to hang parts in the tank. The unit works better if parts are not on the bottom.
NEVER run the tank for even a second without liquid in the tank, they burn out.
You can use more volatile solvents like lacquer thinner by putting about an inch of water in the tank and putting the solvent in small glass, plastic, or metal containers and putting them in the water. The ultrasonic waves will pass through the water and into the containers.
This is great for small parts like trigger units.
>IF< you're careful about sparking and fires you can use ordinary cheap paint thinner as a cleaner solvent.
KEEP YOUR FINGERS OUT OF THE TANK. Ultrasonics and bone marrow don't play well.
This is not instant, so don't get careless and start grabbing parts out with your hands.
