I have a collection of rain jackets from 35+ years of backpacking. Every time a model would come out that would save me 2ounces I would order it. 2 ounces was my cut off point, it had to save that much or more before I'd spend the money. I ended up using a an Ion for the last several hundred miles of trail.....always rain jackets. My experience with ponchos was 36 years ago---this has recently changed with the aquisition of a Packa.
You can read the reviews, study the pros/cons...really all I can say is why did I wait so long for this piece of kit! The latest rendition is expertly assembled and is now my go to piece for rain. I couple it with a pair of MLD gaiters for leg protection and sometimes a pair of MLD mitts. One critical thing is the hood and Packa got that right too.
Weight is 11 ounces and I agree with other reviewers that jacket and pack cover and the Packa wins. I wish I could get by with just a cape but the flapping and the material getting in the way when reaching for something were just too anoying. The Packa has the advantages of the poncho and a jacket and the pack cover is a big bonus.