In reply to mrbird:
I have a Casio pro trek prg 50, barometer, altimeter and compass plus solar powered.
Had it a fair while now and use it for hill walking, scots winter and alps. It's handy to have an idea of altitude, especially if your looking for a direction change or a feature in poor viz. plus it's good to know what ascent you have done / completed.
I find it can get in the way while rock climbing, so attach it to rucksack strap.
Not sure I'd buy one just to use in the alps but good to have.
Altitude via gps can be a bit dodgy so make sure who have a barometer.
HTH Davey
Post edited at 16:13