I bought an Instinct about a month ago and love it. I like the G-Shock aesthetic which I know isn't for everyone but it's everything I want in a watch. The battery life is amazing as you said. I charge it once a week and even regularly using GPS for fitness tracking it's usually at around 40% (it can be extended further by using a GPS mode that polls less frequently). The interface is responsive and straightforward (and button based instead of touch which I personally prefer). Like a G-Shock it's waterproof and appears to be near indestructible. I can't see myself wanting to replace it any time soon.