Super solid and easy to learn if you are an experienced Garmin user like me. I found the HR less accurate than the chest strap - seems to be slow to respond to fluctuations. I like having the smart watch functions that give you read outs on total calories, steps, sleep quantity, and quality, etc. It's also nice to use in a pinch for ride if you don't want to mess with a chest strap or a separate computer.
I own the Fenix and Forerunner also and the Instinct is my favorite. The battery life is great and it is very comfortable. The watch does everything I need it to. It looks great and the bands are very easy to replace. So far very durable as well.
I did not realize a watch could provide as much information as it does. I can't wait to try it while hiking or cycling. Great buy for what it does. It probably does more than I can figure out.