The beeping was just the mode change from baro to alti.
Since buying the watch it only once missed a beat (which was the non-beep on button presses I detailed above), other than that it's been spot on
It's been to the top of Mt. Blanc, it's withstood my ham fisted attempts at skiing (most of the time ending up skiing down with my watch, and most of my arm buried in snow, flying down on my backside!)
It's my daily wearer and will probably stay that way till I get my hands on a black/black seiko monster in the next couple of months, possibly even longer!
A pic of my
Core at the Aguille Du Midi, Mont Blanc.