First blush, only initial experience, but these seem to be excellent implementations of the concept. Using a Samsung S8 Active I downloaded the app very easily and it ran flawlessly and immediately. One minor slow-down was my ignorance regarding ""permissions"" to allow the unit to write an image to internal cell phone memory. The on-screen controls are grossly simple to take snapshots or video. The thumbwheel to control LED brightness works fine/easily. One plus I found is that the ""D"" software you download in the app for the Depstech brand device ALSO WORKS FOR the SHEKAR ULTRA SLIM endoscope. Same app handles both which I find a great feature. I bought the Shekar endoscope for a backup and fitting in tighter spots. The two units / brands both seem well made and very easy to put to use. I strongly prefer that both these brands/models require no battery or recharge and do not depend on wi-fi. Both lack depth of field and would be nicer if they were in focus for greater range of distances for my application. Still super gadgets! In both cases the accessories (mirror,hook, magnet) are flimsy and likely to get lost in a place you do not want to leave it !