Just picked up an Extang Revolution from etrailer.com two weeks ago, I'll break this down into two parts because the seller did a magnificent job.
When I originally looked online etrailer had the cover for $50 less than Amazon, when I bought it was back up to the same price ($499). Ordered online with two-three day shipping ($23). Got an email a few hours later saying the item was not in stock and they were going to ship from the manufacturer. Panicked initially because I needed this thing in 6 days time for a trip. Called customer service who then called Extang, 3 minutes later got a tracking number and the thing was on my front porch in 48 hours. I will do business with etrailer again if they price match Amazon and would recommend folks check etrailer if you're looking for accessories, customer service was top notch in my experience.
I wanted a cover that had support braces which the Revolution does (3). Installation took about 45 minutes, directions were mostly intuitive and it can be rolled up in less than a minute or removed in about 3 minutes, taking the rails off would take 15, it does not cover up the stake holes. It flutters a little bit at highway speeds but most soft covers I've seen do. Water will get in around the edge near the cab and it collects in the corners, everything in the middle stayed dry. Light rain no problem but we drove through some real heavy stuff and it just gets through, they include a foam piece you can cut to fit to stick to the bed to help seal it but some water still got through. There are a couple of videos on youtube that go over the installation which were helpful for me as a first timer. The Revolution is on the high end as these things go but I'm hoping that will translate into long term durability and wear as time goes on.