Showerspass is located in seattle somewhere, maybe you can stop by the warehouse and try one on ?
If you sweat a lot and/or its above 50 degrees, your gonna sweat in either. I guess it all comes down to how comfortable you are in the one you have now. This week its been at the transition point of where its almost too hot to wear raingear in the rain. If you were fine, then the difference may not justify switching.
As something you can measure, hrmmm, id say my base layers are at least 2x as moist when I arrive at work in a goretex as when I switched to event. If the moisture isnt bad to start with you can keep the goretex, if your currently arriving soaked, make the switch
As others mentioned, its not a miracle fabric, it'll still overheat. My arms are what always feel wet first when the temps are above 50. Its also cycling specific with no pockets, so its not something you put on to go to the restaurant at night when its raining. All that said, I'd never go back to goretex.