This news is so old. The new look preview has always been available as an option under the Themes settings.
I like the old one but after some time Google itself switch to the new one so I try to make me comfortable with the new one.
It will always be a bother to some to switch to the new look, but things progress might as well take advantage of it
Gmail New Look its awesome !!! when I heard about Gmail launch new look at the time I change old to new look...
Just switched my gmail to the new version looks pretty good to me , I like this new look it is more clean and the spacing between lines is wide which is less tiring the eyes
I think the old design was a little better, but this one is very cool too. Took me ages to realize the "Send" button was at the top of the page though.
I don't like it at all. It's too contrasty and harder to read. I'm hoping they switch back to the old version.