Today was the first ride with our new DIY rain cover. It wasn't raining, but 40°F and damp would have to do. The kids were so excited that they practically tripped over one another running out to the garage. There was quite a bit of giggling en route to pre-school while they played with the camera and read books. Compared to our normal ride, I couldn't tell that the cover was on, but the kid noise was slightly muffled. (I'm putting that in the pro column.) It looks big, but it doesn't have a profile much wider than my body, so any added drag was unnoticeable.
The kids arrived warm and dry, I didn't have to spend five minutes pre-ride finding hats, gloves, scarves, etc. for each one, and the van stayed parked in the garage the whole time. Win Win Win.