I've slowly become a bit of a watch aficionado. Thankfully when I decided to get a watch case for my dresser, I went with a 12 slot unit instead of 6 as I originally planned, because I quickly surpassed that, and currently sit at 9 watches. I have a number of fashion/dress watches, and with the Fenix 3 HR watch, three smart watches.The Fenix sits on the fence of being a smartwatch in the sense of what a current generation smartwatch offers. Can I speak texts to it, no. Can I control my Nest or other home automation with it, not really (I could set it up as a location device in SmartThings if I really wanted). Does it display information from texts, emails, weather, and so much more, oh yes. I actually am not using the notification content on the Fenix in an attempt to stretch the battery. I have a Moto 360 and Pebble which work better for that purpose if I need that type of device.I was in the market for a device which I could use to track hiking, mountain biking, and walking in regards to activities without relying on my phone. The Fenix has fit that purpose ideally. At the time of purchase, I had no idea that it would sync via Wi-Fi. And this is a huge benefit as I have a Verizon MiFi. So now when I’m out and complete an activity, I can power up the MiFi and have the activity sync with that. It’s smaller, lighter and the battery lasts a lot longer because it’s not powering a huge color screen. Not to mention it has a 4,000 mAh battery, weighs just under 5 ounces, and can charge the Fenix itself. On longer hikes I can now leave my phone powered off and only use it as an emergency phone without needing to carry a giant battery pack to charge the phone since the Fenix will record my routes. This saves me 5-10 ounces of pack weight typically depending on which battery pack I was previously bringing. I’m not a passionate ultralight packer, I do like to go light, but I am a data junkie so I need to feed that passion.I’ve seen a lot of complaining about the heart rate monitor, inaccuracies of wrist based monitors, etc. My Moto 360 was horrid. I could only get a reading 20-30% of the time I’d say. It was so frustrating, I never bothered checking for accuracy and it was a spot reading. So far, my experience is that the Fenix has been spot on. One day at the gym while riding a stationary bike, I checked the hand based monitor against the Fenix. Both measured the exact same BPM rate. I then counted against a clock and my BPM matched what the Fenix was reporting. I also have a Tickr chest strap, which I have not yet paired or checked against the Fenix.GPS accuracy is seemingly pretty good. Inside as expected leaves a lot to be desired. One of my indoor walking routes I take at work when it’s raining, was recorded as me jumping all over the place, likely when it grabbed reception and again lost it. The distance ended up being about correct however, the path was just crazy.ABC’s – one of the main reasons I purchasedThe altimeter is calibrated at the factory. I found it to be off by a couple hundred feet. This was easy to correct within the Fenix. Lidar imagery has accurate altitudes to use for calibration. Google, “Daft Logic Altitude” to find the site which allows you to click on a map and have the altitude returned. Once I calibrated this, it was accurate. I verified by clicking a point at the end of my driveway to get the altitude after doing the correction in front of my office.The barometer is quite useful. I turned on the barometric pressure alarm to notify me of pressure drops of 2mb in a three hour period. I’ve had one occasion when out in the woods where nothing was on radar, and a storm literally popped up ten miles south of me, in two frames on the radar, it went from nothing to yellows and reds. Unfortunately I did not yet have the watch, so I can’t comment if this would have been detected, but that’s the hope when on the trail. The barometric sensor is also used to calculate flights of stairs ascended and descended. I tested starting from the street level walking up to the seventh floor, my office level, and it was spot on.The compass is what pushed me to the Fenix 3 over the Vivoactive HR model. The Fenix has a magnetic compass whereas the Vivoactive is GPS based. Not everyone understands that there is a true north and magnetic north. Depending on where you are on the earth, this angle of difference varies. But for a quick rundown, if you were to navigate to a fixed location three miles away, at a 15º declination, the difference between magnetic and true north is almost three quarters of a mile. Do your research before finding this out in real life.I race sailboats, and there is a watch face in the store for the Fenix. So far is has proven pretty useful, I’d like to see more functionality, so I’ll probably end up writing one myself. But this was another driver for me. I can use the watch to be notified of lifts and headers while racing. I’d like an app to notify of when you’ve reached the layline, etc. Of course the GPS vs. magnetic compasses will be useful here for taking into account for current offset.I’ve been blown away by battery life. When using it just as a watch and an occasional tracking of a walk during the day, it typically loses ~10%. As I write this review, it has been 24 hours since charging, and the battery is at 87%.It’s an expensive watch, and I don’t regret making the purchase in the least bit. I found the button layout to be a bit different in the sense of flow, but I’ve grown accustom to it. I just feel like the back button should be on the bottom left and the up/down menu buttons on the right middle and right bottom. Not a big deal, it works!One gripe, which I'm not going to ding a star for, wish we could do half stars though. It's a proprietary charging system. My guess is that it's probably for water ingress reasons. But if it utilized a standard micro-usb connector, I'd already have one of these cables on trips. So it's another charging cable I have to bring on a backpacking trip, which adds weight. There are aftermarket chargers out there for the Fenix 3, non HR model. The plug into the watch side with a micro-usb connector. So far there are non which have the cutout for the HR sensor on the Fenix 3 HR watch. At the very least, make the OEM Garmin charger utilize a micro-usb connector, or as things are progressing now, a USB-C connector.Oh yeah, it tells the time too. Because it’s GPS based, it follows you across times zones and is always spot on.