When are you going, will it an especially busy time? Will you get there early in the morning? There are some shady places with regular lounge chairs. I have never bothered to get premium seating personally, I don't spend enough time on a chair to make it worthwhile. I don't spend a whole day there either, with an AP I can go for a few hours multiple times. You get a padded lounger with a shade, a lockbox, and someone to take your food orders. Depends on whether that is worth it to you.
I personally don't like the location of the premium seating and I don't like the way the shades are set up, so I would just get there early and get regular seats in the shade.
we got premium seating. It was cheaper on that. day. Our spot was near the lazy river. It was really nice and we liked having a place that locked up our bags and that we had a place that we could crash and didn't have to worry about.