Why would you max out Gyarados over Vaporeon for offense, or would you?
Not sure eevelutions are really worth much dust. You can catch enough eevee at 700+ and evolve them. I have less access to karps so getting a good gyarados has required some powering up. Also so much candy is needed to evolve a karp, that a power-up of an existing gyarados is much cheaper than evolving a new one.
Granted both are for offense so I wouldn't go much about lvl 30, if at all. Both should be over 2500 easily.
Bite and Water Gun have exactly the same stats: 6 damage, 7 energy, 0.5 seconds.
Gyarados has higher attack, but Vaporeon is better after you add in the STAB for Water Gun. The only advantages for Gyarados would be against something that resists water but is weak to dark (if you don't have a fire type to use against Exeggutor I suppose), or if you have a legacy Gyarados with Dragon Breath, which also has the same stats as Bite but allows you to use it more effectively against Dragonites.
Depending on region you might have access to Karp candy more than Eevee candy, I'm in such a region.
There's no use for karp candies other than feeding a gyarados or making another one (or wait for the Gen 6 mega evolution in 2080). However, for Eevee candies, you also have the option to power a Flareon or Jolteon, and stock up for Gen 2 evolutions coming in 2037.
That said, for attacking power, I'd say for mashing down the attack button and not dodging, they are about equal for neutral types like Snorlax. Vaporeon gains stab, but gyarados has a higher attack stat, and the increased power of Hydro pump will probably level out the STAB on water gun a bit. Gyarados will probably die sooner due to less bulk, but as far as speed in taking down a Snorlax is concerned they are probably equal.
For stuff like Arcanine, Charizard, and Rhydon though, Vaporeon does fair better due to the super effectiveness on water gun. Whereas vs Exeggutor (Gyarados is actually useable here!), Gengar, and Psychic types, Gyarados will fair better on bite.
Gyarados also has a higher CP cap than Vaporeon now, so whenever you have a spare one not used for attacking, you can stick one into the gym for a relatively high spot. Both vaporeon and gyarados are garbage defenders anyway, gyarados being the worse of the two.
I don't have too much luck with eeveelutions, have 3 of them at 76-87 IV, 2650ish CP, one with each vaporeon charge move. I also have two Gyaradoses at 2785, 2791 with Hydro pump.
I use them interchangeably but saving the vaporeon for Rhydons and Gyarados for Snorlax whenever my Dragonite is dead.
I move from Gym to Gym taking them down and usually use the pre programmed fighting lineup.
Strangely, that almost never includes Vapes, even though I have some with good moves IVs and 2800 CP.
I find that 3245 Dragonite DB/DC is by far the best attacker followed by Gyarados and Rhydons. I especially love Mud Slap/Stone Edge.
Really, when you see answers, i'm asking if people should looke for wise advices here.
Vaporeon is better than Gyarados for everything except vs grass (where you dont use Gyarados either)
Better base stats. (total 642 vs 624)
Better stat repartition.
WG is the same as bite with 25% stab bonus
Even vs Dragonite Bite/DragonPulse will perform the same as WG/HP
For Snorlax, Vap is better
For Rhydon, Golem and Fire Vaporeon is way better.
Only DB/DP Gyarados can be usefull for dragonites if you dont have Dragonite, Lapras, Cloyster or Alakazam.
And any moveset of vaporeon is a better defender than Gyarados.
Typically Vaperon is better unless you are attacking into a Exeggutor, Dragonite, Alakzaham,
And even then there are better options for those in theory world. However, in Real World, you might not choose to switch every pokemon giving you multiple pokemon with little damage vs 1 pokemon with a Hyper/Max Potion to heal
In grand scheme of things there really isnt much difference between the 2 attackers unless you are attacking into something weak to Water Gun. And even then Gyrados will win, just not as well.
