Looking for a good ultrasonic cleaner

Iv been looking for one as well. How does it work with rusty bolts and greasy parts?? Does it clean enough to remove surface rust and grease?
I had actually looked at them for reloading ammunition a couple times but iv just stuck with my vibrating tumbler. But they dont work very good with boths and such because it fills the threads with media and is a pita to get it out.