i had a ad-20 and now have a ua-5
the ad-20 i think would be safer to stealth in the aspect that the knobs are smaller, don't turn as easy, and the power is on with the battery in
the ua-5 you could tyurn it off fairly easy in a stealth situation i think
i havn't used my ua-5 yet but based on many peoples opinions it will give a better sound then the ad-20
i loved my ad-20 and the mian reason i got rid of it for thw ua-5 was because i wanted one box to run instead of 2--thats a plus to running the ua-5 stealth though imo