My backyard is all gravel and I pick up whatever I see whenever I see it because I have dogs and 2 trailers in the backyard. We still go nails in our tires almost every time we drive back there. This thing picked up so much crap I couldn't even see with every pass. I could open up a hardware store with what this thing found in my backyard. It rolls through gravel easily. Works great!
We're using this on the gravel driveway just under our house that burned down. There are tons (well tens of pounds anyway) of deck screws, deck clips, nails, and other assorted steel mixed in with the gravel. The magnets are very strong and the release works well.
I own a small hardware store and I'd always have nails and screws lying around the floor when I close up the shop so I decided to buy this one. I saved A LOT of time cleaning up when I started using this.
Easy assembly, adjustable handle is a nice feature (but a bit lightweight), and the grip is comfortable. This allows us to roll easily over dirt, grass, and other uneven surfaces without bottoming out.