It looks a well organized space.
PVC (the affordable ones) or polycarbonate (the crazy expensive kind)? I assume that's just one sheet thick, so you're not going to be able to heat it for winter use. But it should extend your growing season by a month in spring and maybe longer in fall. It's quite tall, so in springtime, you can maybe put in a shelf above the bench, to liberate some work space and still have lots of seedlings.
My one concern is the slope of the roof. What's you snow situation?
