Great product. I own it and purchased this one for my son. It is a great tool.
Upgraded to this following an Edge 200 I had for the past 3 years as I wanted the cadence/HR function. Due to having both GPS and Glonass it finds the signal very quickly (few seconds, whereas Edge 200 took couple of minutes at times) and keeps signal better in wooded areas. It works very well but for me there are a few issues: 1: touch screens are not a great idea for mtb. Wiping mud off changes the screen or takes you back to menu (although doesn't stop it recording ride). 2. Despite a huge number of screen options, the customisation of screens is disappointing. So far I've not found a way of viewing time, speed, cadence and HR together. For me there are a lot of superfluous displays such as power. If I could afford a powermeter I wouldn't have bought the 510 instead of the 1000. 3. the power button is not very ergonomic, the shape leads you to press just off the button. 4. Bluetooth connection is difficult to establish at times, but I do not know if this is due to my iPhone, or Garmin. I've listed a few negatives there, but in general use I'm very pleased and it is great for using with a turbo trainer and setting up your own workouts. Being ANT+ and I can use it with Duotrapon my trek.
Now I can upload every ride without taking the computer off, simply the best you can get.