Having lived in the rain most of my life and going through a change-up in rain gear lately Here is my opinions:
First, I just reviewed a SnugPak "poncho" - in quotes as it is more of a "mu-mu" than a poncho. I like it.
viewtopic.php?f=14&t=91689&hilit=snugpak <<review



Our woods are wet, the more we get into them around here the more acclimated we get over the wet. Not saying we are impervious to hypothermia or anything, we just don't care much about a tad of dampness and some of us have adapted to the course of action of wet to dry.
Regarding the rain suit v. poncho: This is how i look at it as I own and use both.
When I wake up in the morning and my POD runs through my head before hitting he deck, I go like this:
"Today, it might rain where I am going." = poncho.
"Today, I am going to be chopping wood and digging drainage ditches all day outside in the rain." = rain suit.
Bottom line being ponchos are for walking to a dry destination in the rain while rain suits are for
being out actively in the rain.
Ponchos are good if you are in sporadic rain or are chilling out in it. I'm walking down some tail, it starts to rain some and get me wet, I pull the poncho out of it's pouch while keeping my pack on, pull it over my head and pack, keep goign down the trail, no drama.
Poncho as shelter? Never liked that idea. I started doing tarp and bivy last year and I'd rather have my Snugpak and a tarp than just a poncho. That is actually what I carry - a poncho, and one of my 2 tarps (an 8x8 or a 10x10).
ETA: I gotta hand it to ODA - he is correct. Just bite the bullet, save your pennies and get a proper sleep system. Took me 20 years to learn that lesson.