Have a Suunto, six or seven years old by now, that has altimeter and compass and admit I never use the compass. It's a bear to calibrate, not terribly intutive to use, and increases power consumption. Hopefully they've improved the UI since because in theory, it would be nice to have. I almost think an analogue watch with magnetic compass might be better.

The altimeter, by comparison, is hugely useful.

Cheers,