*UPDATES BELOW, with some more Pros and Cons.

Original review:
I’m 7 days into the Sapphire Fenix 5 coming from a first edition Apple Watch. Needless to say, I upgraded my analytics game. What an amazing piece of equipment. Very much appreciate the accurate insights, exercise effects, VO2 Max, Functional Threshold Power, anaerobic fitness levels, you name it. This watch tells you exactly what you are doing and can do. And the fact that after 7 days of use with numerous 90 minute exercises, the battery level is still on 20%. Great. For me that's such a welcome improvement over the Apple Watch.

PROS
1. Multisport insights, accurate measurements; pace accuracy is fabulous
2. Countless features and functions
3. 100M waterproof
4. Rugged, beautiful design, looks great on wrist
5. Screen readable under direct sunlight
6. Long battery life (>week)
7. Sync to Connect app is seamless (wifi, bluetooth)
8. Comes with black and yellow straps, easily changeable
9. Its pretty light weight if you ask me
10. Oh, in case you're wondering; all notifications you'd come to love from the apple watch, are on here too. I can even control my music like before. No song searching or voice control though.

CONS
1. Software froze on me once this week
2. Screen was marketed as HiRes, don't really notice that though
3. Colors are a bit bland

All in all a great watch, very happy with it. Full recommend it to anyone who trains a lot. Especially someone looking to upgrade from an AW. Good luck with your choice.

UPDATE, April 20:
On to four weeks with the Sapphire Fenix 5. Watch has become inseparable from my daily activities. Really grown on me. More so than the AW had. I keep looking at it, its stunning black rugged design with capabilities that surpass expectations. Anyone on the fence, go for it. You wont be dissappointed. Do have some small gropes which are more related to learning curve I guess.

PROS:
*Only had to charge it twice this month (thank you!). Used it swimming, cycling, running, walking, strength training.
*I live high-up (8400ft) and the altimeter is spot on, barometer and compass as well. Unit takes the temperature from your surroundings, for example in the sauna you'll get accurate spikes.
*Must say the HRM is also better than expected which produces excellent data analysis on the watch and on the Garmin Connect App (also online). Does need to sit snug on the wrist, if not you lose accuracy. For example, on my daily 8mile bike ride to the office my HR stays in warm-up even though I'm sweating. Pulling the watchband tighter fixes the "issue". Related to using optical sensors, they say.
*If you want more data from running, an ANT+ connected HRM strap gives you access to additional menu for running dynamics, with real time info like cadence, ground contact time, stride length, vertical oscillation. Marvelous.
*Connectivity to more sensors. Im getting the HRM Swim Strap as well.
*BETTER ACCURACY, MORE DATA. Gotta love how Garmin feeds the need.
*Big fan of Segments. Race on commute segments against strangers. Strava also works wonders. Integrates well with online Garmin Connect.
*QuickFit wristbands in more colors.The black one I use while at work. The yellow one is good for the weekend. Looking forward to the leather strap.

CONS:
*First week the software froze, happened once more. So twice in a month. Restart is fast but does delete last 4 hours of HR data.
*Error in software sync pushes your morning alarms from app to watch but not vice versa. This means the alarms you configure on the watch get deleted upon sync with Connect app. Sure this will get a fix, is a bit annoying nevertheless (using iOS).
*Connect IQ apps. Well, coming from AW and its apps Connect IQ makes you feel a bit underwhelmed. Im sure I'll get into it. I wish I could find a better way to use the Navigate app. Learning curve.
*That said, downloaded Garmin BaseCamp to find courses and waypoints to upload to the watch but I was like, nope - I'll save that for later.
*Sometimes the watch kinda renews the connection with my iphone and I get double notified of emails, chats, calendar alerts.

Hope this helps. Have to say that after four weeks I still feel that I haven't discovered half of what the watch can do. Makes me a very satisfied F5 owner. I'll update again once I get the HRM Swim Strap. Good luck with your choice!

UPDATE June 1st:
I'll try to keep this short as its becoming quite a long read. Received the HRM Tri and Swim straps two weeks ago. Wanted to test things out before posting any comments. The HRM straps themselves are excellent, I use the Swim strap in a pool 3 times a week, the Tri I use for running and cycling. Both are very comfortable to fit the purpose of long runs or swim sessions. *I do not live close to open water. Once you get your first access to the extended data such as Running Dynamics and swimming Swolf, you'll be amazed. Especially if you're a first timer like I am. What you cant help thinking though, is that the heart rate data quality becomes so much better with the straps that the optical wrist based data is bound to disappoint afterwards.

PROS
Heart rate real time data a LOT better, changes in heart rate are visible instantly
Running dynamics help you improve your balance and running style* (this is quite a considerable change, actually)
*even on a treadmill.
Pool swimming data is fabulous, not as extensive as Running Dynamics. I attached new Garmin Connect screen shots.
Additional Lactate Threshold and HRV Stress tests are now available
Overall additional datasets make you feel you're entering a professional training environment

CONS
Optical wrist based heart rate accuracy does disappoint, but I doubt it would have been noticeable without acquiring the straps? Not sure.
Swimming heart rate is not available under water, the unit will download HR data after you finish your exercise. This works flawless so no problem at all.

For what its worth, I'm really happy with the straps and additional training data. The graphs are great, the insights in your performance gets better and better. It is quite an expensive combo if you go full fenix5 + straps. Agreed. But I'm using this equipment every day, so I tell myself its money well spent. If you have any questions, by all means. Good luck and stay safe.