weird, my second post has appeared but not the first one.

Ok, I used a ventile jacket in Scotland for many years. They may not be as absolutely waterproof (they can feel damp inside) as a membrane based waterproof but I found them to be about as good as the condensation buildup in a membrane anyway (assuming you dont wear the correct layers under the membrane). However I would rate a ventile jacket much higher for survival situations as they are safer around a fire from sparks and "self-repair" from thorn damage. Both these things would cause the membrane to fail completely and leak in the damaged area. The ventile jacket also gets heavy when wet but this is more than made up for in survival situations by being quiet and enabling you to stalk your dinner if you have to.

As to long term damage as long as they get to dry out they are ok. No worse than your typical army issue cotton or polycotton jacket in use.