Which Exeggcutor power up?

The first, without question.

1.

Definitely the first one.

They are both great. I know a lot of people covet the C/SB set which is legacy (maybe more valuable in trading). However, I personally think ES on Eggy is premier, because I like to dodge, and Seed Bomb is darn good. I used to use it on WP Vapes back when that was such an annoying moveset; now I use it on AT Vapes.

Of all the new moves in Gen2, ES is my favorite. (And ES/SoB is super awesome.)

The first is good on offense and the second is good on defense. Which one do you want?

Ps. Think twice before powering up an Egg for defense since its max CP is relatively low.