3rd floor patios are my favorite because you can relax and eat on the patio and just look over whatever it is your view may be and be pretty removed from whatever is below. 1st floor is my 2nd choice since you can leave the room easily if someone is staying put. And like others said, ducks can come by and visit and chat up a storm. Though I don't like that in 1st floor rooms your privacy is pretty much zero if you are on the patio or near the window, more so at night with the room lights on.
The newer buildings have patios on all 3 floors, but unfortunately all the new buildings are DVC wings now (Booooo!). I have only stayed on a 2nd floor once at the Poly, my 1st trip, and did not like it at all. I'll only do 3rd or 1st floor now.
I also always like to walk up and down the stairs at the Poly too (extra fun and more steps/exercise), so that makes the 3rd floors more appealing to me as well.