I've had both paired for over a month now (since the S3 came out) and love it. The biggest feature for me was Samsung Pay since the S3 has MST support. The Gear app updated about a week after having it which worried me because I thought it would work right out of the box. Even with the Pixel XL rooted, running a custom kernel, and an unlocked bootloader, Pay works fine. You just have to sign back into the Samsung Pay app through the Gear app after every few purchases (which can get annoying when you're trying to be cool.). Anyway, once you set up S-Voice you can send texts through it. I am using Textra and it works fine. I would imagine it would work with stock messenger as well. I can also use S-Voice to make calls through the stock dialer. Haven't used it for emails yet.
There have been a few things on the watch that have bothered me. If I turn off the call feature (because taking calls through the watch is most times inconvenient) then turning the ring doesn't work to answer or reject calls. It would be nice if you were to turn it and the phone would answer in speaker mode. Also, my watch always locks on me. I think with the factory strap the watch rides up too high on my wrist and a tattoo there messes with the sensors and the watch thinks i'm not wearing it. It's annoying to have enter my pin everytime I want to look at a notification. I'm am ordering another strap which I hope will hold the watch closer to my wrist and tighter to the skin which I hope will help.
Battery life has been great with me, but I don't have LTE, Wi-Fi, or the AOD on. Through regular use from 0700-2200, I put it on the charger and it has 87% life left on average.
At the end of the day, I love it. I just wish Samsung would ditch Tizen and go with Android Wear. I'm sure they could make Samsung Pay work with Wear.
