The sad truth about all rain gear is that if you're hiking/moving and generating moisture inside of it, especially if you're wearing a backpack, you'll soon be as wet inside of the rain gear as you would if you weren't wearing any. Breathability works pretty well if you're skiing and the outside air has essentially zero humidity and the temperature differential between inside the rain gear and outside is very large. Doing anything that causes sweat while wearing rain gear in the absence of such differentials results in you being wet one way or the other.
Back in 1978 I wore my first GoreTex rain gear while spring brown bear hunting way out on the AK peninsula. On one long day far from camp while up in a snow field chasing a nice bear I damn near died from hypothermia because of the moisture failing to pass out through the fabric.
Since then I've owned 100% waterproof heavy fishing rain gear, Sitka Gear rain gear, Kuiu rain gear, HH Impertech, and REI E-vent rain gear. It's all a compromise so don't expect to remain fully dry and comfy inside if you're working up a sweat in the rain. So far the best option I've found after 4 decades of buying and trying everything is E-vent. YMMV so take it for what it's worth but that's my opinion based on first-hand experience.
