Excellent and tough - minor accuracy problem. Calibrated at parking lot (9,640) indicated 13,860 on summit of Missouri (actually 14,067). Could be temperature issue - it was warm at car but snowing and blowing at summit. Easy to calibrate. Controls easy to operate, functions easy to find. I use it to navigate - can't say better than that.
As far as features go, this gadget has them all and they all work pretty reliably. However, in terms of usablity, I find the interface to be overly complex and not always consistant. Sometimes you single click to enable a feature, sometimes you hold the button for two seconds.... If you really want to use all the features you have to keep the cheat sheet handy, or have a much better memory than me.
The only real "missing" feature is that you can't check an altitude log in progress (ie. how many runs have I skiied so far today.) You have to stop the log to see any results.
All the same great features as my Vector with the added heartrate monitor. There are alot of functions but with a little practice and study you will learn the ones you need and forget the rest.
It also is as accurate as any I've used.
One great feature is that the chest strap is made by Polar and is compatible with most healthclub cardio machines. The machines will automatically read and display your heartrate while working out and wearing the chest strap.