I've had it since Christmas. Bought it for hiking in Snowdonia, got through 5 days of that in (mostly) pouring rain, all the wet riding I've done this year, plus more hiking and camping etc.
I'm not kind to things like this and it's still pretty much mint condition.
I use this: http://www.gelert.com/gelert-phone-case-784062
you can still use it through the case in a pinch - which is good when fumbling with wet hands.