most of my whole family has the precip jacket. it IS TOTALLY WATERPROOF, ... however, it does not breath terribly well, and on highly aerobic activities, condensation builds up on the inside giving you the feeling the jacket is leaking. knowing how and when to use the pit zips to vent the excess humidity is essential. i use the jacket for hiking, backpacking, cycling, and cross country skiing. i also have some gore tex jackets, but they are much bulkier and not as conducive to ultra light outings, and even they suffer from interior sweat condensation under certain conditions.