My experience is that the GPS chip in the Curve 83xx is very accurate
but also very weak
. It loses the satellite far more quickly and easily than my regular GPS receivers do.
The slightest amount of cover will cause the satellites to be lost. It also takes a much longer time to acquire the satellite lock compared to a dedicated, recreational grade GPS receiver.
Having said that, while I wouldn't count on it routinely in the woods, I would certainly be glad to have it if I was lost in the woods. It would be better than nothing.