I have both an RCBS vibratory and ultrasonic cleaner. The ultrasonic is excellent for cleaning guns/gun parts, but not so great for cleaning brass (especially the primer pockets). Also, ultrasonic cleaners are just that, cleaners. They don't shine parts/brass. I know lots of folks use a combination of ultrasonic cleaners followed by vibratory cleaners in walnut media for their brass. For brass I'll either be buying or making a rotary tumbler using stainless steel media pins as I hear they work excellently for brass.

If you're considering an ultrasonic cleaner, research which solvents to use for which applications; the wrong solvent can/will harm finishes on parts and weaken brass. If you'll use it for brass, remember to de-prime before putting in the ultrasonic cleaner as the primers tend to absorb/hold moisture. Also, while the price goes up dramatically with the size of the cleaner, consider what you plan to use it for before choosing one too small or you will be regretting the smaller size and looking to upgrade (pay once, cry once). I learned that lesson the hard way.