I originally bought these for an upcoming bicycle tour in Switzerland. However, I've been using them the past few weeks for my weekly night time MTB rides. They keep my legs warm and comfortable and if I start to overheat the generous leg vents add needed airflow. I've also encountered some decent rain on a few occasions and they have kept me much drier than anticipated.
At first I was concerned that the lightweight material wouldn't stand up to the thick brush and Manzanita we have in SoCal but they've held up great so far. They have even held up to a couple of OTB crashes into the brush as well!
Overall I'm quite impressed with these and have purchased a few other Gore items too. Every one of their products has been impressive!
Update: These really came in handy on my Switzerland tour. I ended up riding in some sleet and snow when going up Albula Pass and these kept me warm and dry.
My only complaint is that the Velcro is really aggressive and rough on my gloves and jerseys. After I got home my gloves were shredded from the contact with the Velcro. Still 5 stars though!