Nothing. I spent a lot of time getting to level 40 and feel it was wasted. There seems to be no difference between level 30 and 40 as far as Pokemon CP goes in the wild. I did not use a bot and spent money on incubators, lures, and a lot of lucky eggs. The level rewards are not worth the time once past 30, as you get more items at 20 then 35 when it takes so much more XP. I enjoyed the gen 2 but really feel they let you down when you get to higher levels. A Legendary character or at least higher CP once you hit 40 would have been a nice reward. Very disappointed.
Felps80 about Pokémon GO, v1.29.1