I'd be curious about people's experience with ponchos. I always just dismissed ponchos without much thought, figuring that they would be a hassle if riding much over 10 or 12 mph or riding into a wind even at lower speeds. Am I wrong about that? What combined bike/wind speed does it become a problem if it does at all? How about cross winds?
The pictures always show riders riding in a very upright posture are they cut so they also work for someone who rides in a much more aggressive posture?
You mentioned not using the hood. I have always been inclined to not use hoods on my MTB riding/racing even in winter all weather riding. I got in the habit of using a swim cap for whitewater kayaking in cold weather and that carried over to other cold weather sports in wet weather for me. The thing is that without using a hood it is nice to have a collar that can be cinched snug so cold water doesn't run down your neck. I don't guess there is enough demand that anyone will sell a poncho with a cinch-able collar though. OTOH, it wouldn't be too hard to convert a tarp into a poncho.
I wonder about the actual weight Amazon lists it at 8.8 ounces and Exped at 340g (11.99 ounces).
I am pretty weight conscious when it comes to gear so it would have to be either a really needed item or maybe used as a shelter tarp and a poncho. I typically tour when/where rain isn't too likely to be an all day every day thing so usually it is a matter of toughing out a day or a few hours here or there. I don't find toughing out some rain in 50F+ weather to be that bad with my current gear. I guess if I got 40F, high winds, and hard rain I'd be in trouble trying to ride with what I typically have along, but I'd hole up for the day if that happened unexpectedly. I might use a poncho if I were to tour in a really rainy place where daily all day rain was a given.
In the past I have generally used "rain gear" that essentially functioned as a windproof barrier to keep the chill off. The assumption being that I'd be wet either way either with rain or sweat. After all I am usually dripping wet on a dry day when riding. I have a range of pants/jacket(windshirt) combos that range from 5 ounces to close to a pound and usually take something at the lower end of the scale.