I think Rachel has already decided that she doesn't want to use either a rain jacket or a standard poncho and her dilemma is to choose from among the
altus, the packa, and the ferrino. I had the same dilemma and ultimately just bought the Ferinno because I found a great price online.
Unfortunately, I just don't have the opportunity to go hiking in heavy rain too often where I live, so my trial will not come till next year on the Camino. Standing in the shower with it makes sense only if I am concerned there might be a defect, because the real problem with water inside the jacket comes from my own perspiration.
I may be wrong on the science here, but I ultimately decided that just because two pilgrims report a lot of condensation inside the
altus and three report a lot inside the ferrino, that doesn't tell me anything about how they will work for me.. How much each one of us sweats inside the jacket will depend on our own physiology, our weight, our pack's weight, our general fitness level. So what is really the only way for me to know which one is better ventilated is for the same person to walk in the same conditions in all three of them. Falcon, I think you have all three of them so you could perform this experiement for us.
I guess I got to the point that the differences seemed to be idiosyncratic and personal, so I got the Ferrino and my assessment is just like kitsambler's. I'm looking forward to lots of rain next year so I can give a real report, but of course it won't tell you whether I would have had less condensation inside an
altus or a packa.
I'm not saying we should stop obsessing about this, though.
Buen camino, Laurie