Every so often I see people discussing the accuracy of altimeters, so as I was waiting for my mate Yair to send his "yes we are still alive" Spot message (for goodness sake , the worst thing it can happen in the Aussie bush is that you die or set fire to it...) I took the opportunity to take a pic of our instruments.
(there is a Kestrel 3500 missing from the pic, the one with the due point thingo)
Anyway, as it happens during the 4 days walk my Casio, his Suunto and the two Kestrels were usually within 10 m of each other, the two GPSs were 20-50 m off.
In this pic , my GPS was still adjusting and oddly my Casio let me down. The Kestrel has the closest reading .