I don't necessarily agree across the board, the jackets don't all fail, not all eVent (or other WPB) jackets are created equal. I don't know if the failure is exactly BECAUSE of the UL nature of some jackets, but basically I assume that it is, based on my limited personal experience and that of my friends. All of the lighter weight jackets that I've ever owned or seen that are a very thin layer of fabric and no real coating eventually fails. This type of jacket also wets through faster. I find that there are certain jackets that have, maybe an extra layer of fabric, maybe something else, that allows them to perform better and for longer. One such jacket is my eVent Rab Drillium jacket, that I bought many years ago. In fact I bought the "prototype" sample jacket from a store before they got their shipment. The fabric has a backing that basically puts some distance between you and the outer edge of the shell. This in itself seems to greatly increase the breathability, and it actually entirely eliminates the "clammy" effect you get when your jacket feels like a garbage bag of thin material on your skin when its raining or when you're sweating. Problem is, this type of jacket doesn't come in 6-8 ounce versions. The fabric is heavier. You see it in jackets between 11-13 ounces and up. Westcomb makes some polartec neoshell and event jackets that also exhibit these traits. These types of WPB jackets are extremely different in feel, performance, and durability. Personally I would never ever cut the extra ounces out of my pack in this category, simply because I know the durability and reliability are there. I wash the jacket after every few hikes where it gets regular wearing/use (IE after I sweat in it) and it has stayed good for a long time. I haven't had to refresh the DWR in a while, but its probably due for another coat soon. Does anyone else know what I'm talking about with the difference in jackets using stronger fabrics with backings/layers and the jackets that do not use them?
(edited for grammar)