Vimeo inclusion quirks Answered
It seems Vimeo and Instructables are not the best of friends just yet. I hope they are working on these issues so that including our Vimeo hosted videos is a less frustrating experience in the future.
Only If you use the new editor you can embed video with the Vimeo URL, or even simply posting the link in the body will place your video. Save right away.
But then... anytime you open your Instructable to edit it moving forward, Instructables removes the video and saves the Instructable (Awesome). You'll have to add it back in again and save for it to reappear.
Youtube quality is always improving, but the ad-free playback and greater controls makes Vimeo a winner in my book. I hope Instructables figures out how to get it's editor to play nicer with Vimeo videos sooner than later.
Mac 10.9.1 , Chrome Version 27.0.1453.93