Sceptile or Eggy

Venusaur with Frenzy Plant.

I like them both and have one of each maxed out. I get more use out of my FC/LB Sceptile though, for fast sweeping demotivated gyms.

I'm also working on maxing a FP Venusaur. I like diversity.

Sceptile candy is harder to get so will take longer to power up.

Best grass attacker, Venusaur with Frenzy plant.
Between Sceptile and Eggy, the second. Sceptile has specific niches where it may shine, but Exeggutor is overall a better grass attacker almost on pair with FP Venusaur.

I kinda hate Exeggutor. He always bites the dust on his second Solar Beam and then that big chunk of damage gets restored to the raid boss. This has screwed me over so many times.

In practice, I got much better results using Sceptile against Omastar than I did with Exeggutor and now Venusaur with FP means I never have to use him again :D

Sceptile.

Eggy is slow. Often SoB is to slow to use second time before faint on him In Omastar raids sceptiles and soB Venu was better. FP zaur is now the best.

Frenzy venusaur is crazy good as a grass attacker.
Sceptile is pretty fast, good for dodging and multi bar leaf blade deals consistent damage.
Personally I never liked eggs, feels too sluggish despite damage dealt, just like rhydon. Most of the time can’t fire second solar beam if not powered enough. Bullet seed isn’t the best fast move.
Groudon deals good damage but still feels wrong as a grass attacker. Shame on you earthquake.

They all have different typing and resistance and advantages depending on situation

Venasaur with frenzy plant