Fenix 5/5X Purchase

You can always check out the new Forerunner 935 its been getting good reviews and people are really happy with the gps accuracy and doesn't seem to have the ANT drop outs the Fenix 5 is suffering right now.

Basically a plastic Fenix 5 and cheaper.

It's possible that if you're coming from a Forerunner you may find the GPS on the F5 to be less accurate.
Having said that - I moved from a Forerunner 235 last year to a Fenix 3 and I found the GPS to be better on the F3.
But again - having said that I have seen my F5 is *slightly* less accurate for GPS tracks than my F3 was. For my standard road run at least. But then I did a trail run in a pine forest over the weekend and the F5 tracked better than my F3 would over the same course.

Most of the GPS complaints seem to be related to instant pacing, but I'm guessing that's less important for your trail running. It will track your overall distance and tracks just fine.
The Ant+ and Bluetooth dropouts seem to be widespread - I've experienced them with my Wahoo TICKR Run HRM chest strap in both BT and Ant+ mode but my Garmin HRM-Run4 chest strap has been rock solid.

The F5 will work while charging, but the current charging cable set-up makes it impossible to charge it while still wearing it, which may be a consideration for those longer ultra runs. DC Rainmaker mentioned Garmin are looking at selling a wearable cradle to allow charging while wearing the watch but it'll probably cost US$100 or something ridiculous, though it does charge fairly quickly so maybe during those 100 mile runs you could charge it during your rest breaks.

Current owners on here would you purchase the Fenix 5 if you were given a chance to return it for full value?

Yeah, I would!

Get a 5X!

I've owned a Fenix 5, and now own a 5X. I returned the 5 after numerous attempts over several weeks to get it to work properly, ie. as advertised. The sensor connectivity issues drove me nuts, especially bike sensors. Didn't matter whether I used BTE or ANT+ sensors. And, returning the 5 was a PITA for me as I didn't buy it locally (lesson learnt!). The 5X has worked perfectly from day one, no connectivity issues ... no issues at all ... and I get map functionality too :-) With the 5X, I feel like I'm getting what I paid for - that wasn't the case with the 5.

I previously owned a F3HR, and upgraded to the F5 Silver. For my needs (working out 6 days a week: swim, bike, run) it works great. The GPS may not be as accurate as the 935 (honestly I don't think most age-group athletes will have any issue with the GPS accuracy on the F5), but I am willing to sacrifice some GPS accuracy for the nicer look and metal casing of the F5. The F5 looks like a 'regular' watch, and not a plastic 'workout' watch.