I bought one when they first came out. Seamed to work fairly well and light weight. One day in the middle of the lake it just started going crazy for no reason.
Sent it in for repair

? when it came back I traded it off on a better more expensive machine I was spying on. Now I have another machine starting to do the same crazy dance intermittently. After 40 years of detecting and many detectors I can tell when something inherently wrong is affecting the performance.
I will take this other machine apart myself and do some testing in my spare time at work.
My main work horse machine has been hitting gold and silver left to right.
When it comes to bottle caps; I dig them all up! Its' not that hard. Save them up and recycle them.
I let mother nature clean my caps and flip tops. Toss them in the big flower pots leave in the weather, shake the pot once in a while.
I believe in a cleaner hunt field; you will find those old precious targets the old timers
the generation before me walked over.
I have had triple targets in 1 scoop with that scratchy signal most detectorist' skip right over.
ATPro if you get a good one a lot of people enjoy them.
I like to know what the technical problems are. Shorted wires, cheap electrical varnish, bad O-rings etc.