Now, the problem I have with reviews on Amazon is that despite if a product having 4 and a half stars, it will still show a variety of fluctuating appraisals. For example, if I wanted a toaster, I'd get at least two contrasting reviews: one saying "This toaster is amazing! It does toast, cleans the sink for me, takes the kids to school, and is amazing in bed!" and the other "This is the worst toaster I've ever had. It burnt my toast, cheated on me with my partner, and caused a second Cold War." The Bosch Truvo is unfortunately a victim of these kinds of assessments.
That being said, I decided to brave the purchase and put the reviews aside. The first impressions were good, in that they actually include the three AAA batteries required to power the scanner; very courteous. I slotted them in, flipped the massive "On" switch on the front, the green light on the front came on instantaneously, and I was in business.
The instructions detail that the light remains solid green when it doesn't detect anything, changes yellow when there's something close, red with a continuous shrill tone indicating metal that increases in tone as you get closer to said metal, and flashing red with rapid beeping for detecting wires. I decided to test it on both masonry & plasterboard (both are in my house) wall, and sure enough, it detected metal & wires. Now, it didn't just do it sporadically anywhere on the wall, it did it consistently on every spot where it alerted me to something behind and stopped as soon as I took it away. To make sure it wasn't just blind luck, I also tried scanning anything that was metal or wiring outside a wall, and again, it gave definitive results with the appropriate color & sound codes.
I really don't understand how people who have used this product have had such varying results; I can only possibly put it down to different properties, walls, and even user behavior; who knows if anyone looked in the troubleshooting section of the manual or handled the devices like gorillas?
In conclusion, I would consider this device a successful purchase and I definitely got my money's worth out of it. I would recommend it to anyone who needs to put up shelves or a TV, and I recommend to take online reviews with a pinch of salt; even this one you've just read. I got what I needed out of it, you possibly can too.