These days I take an OR Helium rain jacket and pants but they almost never are actually worn, very little rain here but never left behind for safety purposes. Can’t do without my old Patagonia Houdini which is a MARS edition and super breathable but not water resistant. I wear the Houdini as a wind shirt most winter mornings but never tried it with the OR rainwear.

If you want a very good poncho that does cover your arms take a look at the Snugpak Patrol poncho. I really like mine. It is more protective than any other poncho I’ve tried. It doesn’t morph into a stand alone shelter though and is only for wearing. It doesn’t flap in the wind while wearing and your arms will stay completely dry. It covers me down to my knees.

Windshirts can be waterproof for the first few weeks but always lose that ability fast and I’ve never had luck with additional treatments of DWR. They are only comfortable for heavy exertion in cold or windy conditions but I need dedicated rain gear for a wet storm.