Goretex (and many other brands) incorporate a wp/b membrane plus a PU layer that may be laminated or coated on. This PU layer does not render a garment non-breathable -- it can still breathe -- but the breathability is, of course, compromised to a degree.
The higher the differential in temp and humidity between the inside and outside of the garment, the better the garment "breathes". So a wp/b garment performs the best in cold and dry alpine environments -- and it performs not at all in warm/humid climes.
eVent is the newer technology. The eVent laminate makes a garment rainproof -- without need for that additional PU layer. Breathability is significantly higher at a wider temp / humidity range.
Of course, there is no miracle fabric out there. If you think about it, you can work up a sweat wearing the thinnest tee shirt hiking up a mountain slope. But in terms of keeping you dry longer in a wider temp/humidity range -- skip Goretex and the myriad of laminates/coatings that incorporate PU -- and go for one of the following that maintains waterproofness without a PU layer:
2. MontBell's Breeze Dry Tec