What's better for vaporeon and other water types?

It states exeggutor on this site which is probably correct. I prefer venusaur with its quick attacks and double grass. It's pretty much made to take down Vapes.

Exeggutor is just so clunky for attacking, maybe I just got tired of using it. It's good against everything.

Removed.

This is mostly a question of opinion.
But my opinion would be venusaur, perhaps because I like faster quick moves when attacking, they allow more efficient dodging.

Vine Whip true DPS - 13.85 x 1.25 (super effective) = 17.31 DPS
Vine Whip EPS 10.77

Zen Headbutt true DPS 17.14
Zen Headbutt EPS 8.57

quick move DPS is basically equal but Vine Whip gets to 100 energy 2.38s quicker which means that after Solar Beam you also have 2.38s of Vine Whip DPS before Exeggutor's Solar Beam finishes.

Exeggutor's Solar Beam does 5.3 more true DPS and the move lasts 4.90s so it does 25.97 more damage compared to Venusaur's Solar Beam.

But Venusaur has an extra 2.38s of Vine Whip DPS which does 2.38 x 17.31 = 41.2 damage, which means in the same time frame a Venusaur does more theoretical damage than Exeggutor, and you'll also have more energy going towards your next Solar Beam.

Things not considered is energy gained from receiving damage, which Exeggutor will receive more of due to it's lower defences, which might mean that it receives more EPS than Venusaur, and also the fact that energy is gained in discrete amounts rather than continuously.

e.g. if you're at 97 energy and you need 3 more energy to use Solar Beam, despite Vine Whip giving 10.77 EPS, that doesn't mean it takes 3 / 10.77 = 0.28s to gain 3 energy, because you can't do a third of a Vine Whip's worth of damage and energy, it would still take another 0.65s (the cd of Vine Whip) to gain the energy for Solar Beam.

This favours Venusaur though since Vine Whip only adds 0.65s to the damage cycle while Zen Headbutt adds 1.05s, making Solar Beam's time a lower portion of the damage cycle and therefore it increases the DPS by a lower amount (although only very slightly).

Also dodging isn't considered. If you're the type of person to dodge every quick move, then what matters is the whole number of attacks that you can get in between each dodge.

For example if the enemy's quick attack cooldown is 1.5s then you can get 2 Vine Whips (2 x 0.65s = 1.3s) or 1 Zen Headbutt (1.05s) and still be able to dodge.

You can't do half a Zen Headbutt and gain half the energy, so with Zen Headbutt you're gaining 9 energy in between each dodge, compared to 14 of Vine Whip, which means that Vine Whip ends up 55% more energy (14 / 9 = 1.556) than Zen Headbutt in actual gameplay, compared to the theoretical 26% value when you only compare their EPS (10.77 / 8.57 = 1.256).

I consider Venusaur the best vaporeon's counter in the game. Exeggutor has much higher stats, but the lack of grass type quick moves makes the hole difference to me. And besides being supper effective against waters, Vine Whip generates energy faster and make dodging much easier.

Eggy is a beast, but I would guess the Venusaur with that moveset would still be a better counter.

The best Vaporeon counter is Victreebel with Razor/Solar. Venusaur with Whip/Solar is almost as good. Vileplume with Razor/Solar would come 3rd.

Then, of course, any Eggy with Solar Beam is also a beast against them.

I have a 93% Eggy with Conf/Solar, a 93% Victreebel with Razor/Solar, a 91% Vileplume with Razor/Solar and also a 96% Tangela with Whip/Solar. I have a huge squad for Vapes/Poliwraths and Slowbros.

However, I always end up using just the Eggy and the Victreebel.

Try Victreeble with Razor Leaf Solar Beam. I have one and it shreds Vaporeon.