Since Oct 2011, Im been using it for my training. Be it running or cycling or some heart-rate workout.
I'm love my Polar RCX5.
I used my Polar RCX5 in TMBT, and the GPS lasted me for 14 hours plus before battery die off. (ops.. my TMBT race report, it's still in progress, sorry about that)
Without fail, perhaps it's my training intensive schedule, my Polar RCX5 on board memory always hitting to full memory alert in end of the month! Weee...