Why was this chosen as a matchup?
All three of these Pokemon have the species name: The Sun Pokemon.
Which one do you prefer?
Which has a better design?
Which one is more useful?
Which one would win in a battle?
Overall Winner:
As for my answer:
Which one do you prefer?
Espeon, by a long shot. It's my favorite Pokemon.
Which has a better design?
Espeon, it's adorable. Volcarona is pretty cool, though. I'm not too fond of Sunflora.
Which one is more useful?
Espeon and Volcarona are both pretty useful. Espeon has Magic Bounce and with a few Calm Minds it can OHKO a Dragonite, but Volcarona is extremely powerful and a good sweeper. LOL @ Sunflora for being useless.
Which one would win in a battle?
Volcarona would beat both Espeon and Sunflora. Espeon would beat Sunflora if it was just the two of them.
Overall Winner:
Espeon~