Adrian,
I have both an old style and a new style (Alpha Green Special Version). In size XL, my old version weighs 4 oz and my new version weighs 4.5 oz. I much prefer the new style for its improved protection in stormy weather.
The new high collar, that the hood stows in, allows you to use the hood bungees to adjust the neck size with the hood down. It also allows you to cover your face to just below your nose with the hood down or up.
I wore the new version on a week long backpacking trip recently. It was the only outer layer I brought because the long range weather forecast didn't show any precipitation. The trip included a snow storm with 45 mph winds. The Houdini in combination with a Mont-bell XL under it kept me both warm and dry.