Mine worked pretty well too agnogel. Been too lazy to post a review on it. But here are some thoughts I have regarding it. First, yes it functions well and does what it says it supposed to do. But here is what I wish it was capable of doing.
First, I wish it had the ability for me to be able to focus (manually of course for the price). The focus is fixed on it and you are bound by this range. I sure the expensive ones come with remote focus cababilty.
Second, the four LED's are not as powerful as I would have hoped. But I guess I could supplement the lighting.
It would be nice if it did have a slight wider angle field of vision (as stated in the video) than normal.
Anyhow, I did look inside one of my pistons before I took the top end apart. It basically confirmed to me that the pistons had carbon build up. Was not able to really determine the health of the cylinder walls using it because of the fact that I could not focus for the needed distance and not powerful enough lights.
I would have like to have had it when I cleaned out my tank to make sure it was debris free.
Haven't tried it for plumbing.