Hi Jonathan
I should say to begin with that I haven’t tried the Packa, but there are a few reasons that it isn’t my first choice:
– it cannot vent as well as good poncho, its long, its restricted around the backpack and even though it has large openings under the armpits it is not like a poncho where you can have the whole side open.
– The main adjustment of ventilation is opening it in the front at the chest. It will get your chest wet and it will not keep things such as camera that you keep available on your front dry. I prefer to adjust ventilation on the sides
– You canĀ“t get a flat rectangular sheet of it. That much reduces alternative uses.
– You cant get your pack off and on without removing it.
– It is more difficult to access gear with it on compared to poncho.
– It is a lot of fabric.
An advantage the Parka has over a poncho that seems useful is that you can take it off but still keep it on the backpack so it is easily available if it starts raining again. As I write this now I am thinking that nothing stops me from attaching my poncho to the backpack. I would give me the same advantage plus having a maybe easier way to put it on when windy, plus an easy way to keep it in check when windy, with the downside that it increases the fiddle factor if I want to take on/off the backpack with keeping the poncho on. Hmm have to think about that one.
I guess it is also a personal preference for simple solutions when they exists and works well.
I am sure the Packa is warmer if its cold, however my only requirement for my rain gear is to keep me reasonable dry hour after hour day after day in all weather and in as large temperature range as possible. If I am reasonably dry, I have other means to stay warm if its cold.
If that is really not achievable, the rain gear must definitely stop me from becoming wet from the outside, but the latter is not at all the primary goal, then I could just use any non-venting rain jacket. It rather goes as a failure that is possible to handle without risking your health.
On most of my trips the temperature can vary between about 30 F and 90 F. Above something like 70 – 80 F rain gear isn’t really necessary if you are on the move, but in order not to get wet from inside up to 80 F you really want your rain gear to ideally provide no warmth at all.
Not that a poncho is ideal in all those conditions and solves everything, but it is the best I have found and so far it have worked better than I initially expected. But I am still trying to mitigate the downsides (obviously, staring this thread).