Keep in mind this is very subjective because it is "feel". But the 50s seemed to have been a little more unpredictable vs. the 64s in gusts. 64s seem to have this "gentle pressure" feeling and the 50s seemed to snap a bit more with the gusts. I have a friend who has mentioned the same thing when riding a newer set of semi-deep rims similar to the 50s. All anecdote but that is just my experience.

They do roll quite fast though. There were times I was impressed at the speeds I was hitting with cross/head winds the other day.