I get to test a lot of great smartwatches for my job, but it’s only the very best watches that stay on my wrist after testing. When it comes to my own marathon training, the Garmin Forerunner 970 has been my go-to for almost a year now. This year, I used it to train for and run the London Marathon, and it proved both impeccably accurate and genuinely useful throughout the past five months of training. After all this testing I can’t speak highly enough of the Forerunner 970, but it is expensive at full price, so I’m always keeping an eye out for discounts. Right now you can get the Garmin Forerunner 970 for $649 at Amazon , which is a $100 saving and matches the lowest price I’ve seen on the watch. The Garmin Forerunner 970 is the top-of-the-range Forerunner and so is packed with all of Garmin’s best sports tracking and training analysis features.…