GPS Watch selection in 2016 fall ~ my selection!

I've been using this for almost 4 years ....

   Although my current GPS watch Forerunner is still working well, I am considering to get a new one based on the test result of the built-in heart rate sensor in vivosmart HR and some advanced feature in the new product line.
   I was talking about a generic points in the previous posts, today, I am writing more my personal expectation.

My usage? 

   First of all, I list my usage and requirements:

• Running including a daily training and races
• Prefer to download training plans on a calendar on Garmin Connect
• The race is probably up to full marathon and based on my performance level, it is probably around 5 hours
• Daily activity tracing especially monitoring heart rate 24/7
• Hiking, but I probably won't try very long day hiking
• The maximum walking time a day would be up to 10 hours such as going back to the trail head after Mt. Whitney summit attempt from Trail Camp
• Want to have built-in wrist based heart rate sensor to get my heart rate data during sleeping in Mt . Whitney hiking.
• Interested in getting extra running dynamics data
• Interested in a feature to estimate lactic threshold and maybe VOmax extimate as well

   Due to the second item which is downloading the training plan, Forerunner 35, vivoactive HR and vivosmart HR+ are out of my selection.  They cannot support the feature.  Also, to meet the other expectations, the candidates are Forerunner 735XT or Fenix 3 HR.

Which one would be good for me?

   The both of them meet my expectation.   Forerunner 735XT is lighter than Fenix 3 HR.  The weight of Forerunner 735XT is about half of Fenix 3 HR.   However the battery capacity of Fenix 3 HR is larger than the Forerunner 735XT.  Fenix 3 HR has an altimeter and a compass.  Fenix 3 HR also looks better.  The price of Fenix 3 HR is about USD $150 more expensive than the Forerunner 735XT.
   It is really depending on person's preference and the price.
   I prefer Fenix 3 HR because of a better outlook as day-to-day watch and larger battery capacity.   I am not sure if I really use the altimeter and compass, but they are nice to have.  I plan to get Fenix 3 HR and do some testing.