In reply to chicken88:
I have an Ambit3 Vertical
Notes:
It doesn't do on the wrist HR tracking.
It is waterproof to 100m
The battery won't last long if you put it in GPS mode - you can vary the sampling rate
Barimetric and GPS altitude... but no storm warning
Mono screen, not colour.
Suunto claim:
Best: ~1 sec fix interval, highest power consumption - 20hours
Good: ~5 sec fix interval, moderate power consumption 
- 30hours
OK: ~60 sec fix interval, lowest power consumption 
- 200hours
For hiking I would be happy with OK, but distances would be out. You can tell the difference if you are running between best and good VERY easily.
Will continue to work if just charging from USB using battery pack, from reports.
It will do OSGB or LatLong and many others. It will give you a position! Many of the cheaper ones will not do this. They will tell you how far, but won't give lat long / OSGB at the time, only afterward when connected to phone.
Comes with HR strap, but doesn't have on wrist HR. For walking I don't care about HR - miles are more important. I use HR for running, cycling and surf-ski. Optical HR is OK for running, but seems to have problems still with cycling according to reports. (My wife has TomTom OHR and is very happy - its meant to be one of the best). HR strap about the best out there in terms of comfort and size, but still a strap.
***Probably not as good as the Fenix... but I'm semi-sworn off Garmin products after far too many have failed on me and my friends. ****
£219 on wiggle. Original version came with poor strap, replacement has been redesigned to stay on wrist properly!!!
I fit a Brotect screen protector to help keep the screen readable after knocks.