I returned my Spartan Ultra because I wanted to check out either the Spartan Sport Wrist HR or the Fenix 5.
My experience with the fenix 3 and the fenix 3 HR have been troublesome over the last couple years. Many software issues and inconsistencies has made it so I could not trust using them.
My experience with Suunto has been much better. I have an A3P and had the SSU for enough time to know that they are more accurate and dependable. They also work every time I use them.
I like the features of the Garmins, but many of them don't seem to work right.
I was hoping the Fenix 5 would be different, but looking at forums I see the start of all the same types of issues that you see on the Garmin forums for every device they sell...
this don't work... that don't work... and so on...
I am watching the forums closely before making a decision, but leaning more toward the Spartan Sport Wrist HR when it becomes available at the end of this month.
I would like to hear other opinions as well.