I didn't want one, but the dealer had the car I wanted with one so I bought it. I'm glad I did.
As much as it's great when the weather is nice, nothing is better than leaving the cover open on a cold winter day and having the sun warm the car up.
Also, I am 6' 1" and I have TONS of headroom. I'm not sure how people have their seats adjusted, but one of the first things I noticed when I drove the car was how much headroom there is.