>>48375338Master Venusaur here.
Sylveon is scary, but Hypervoice kinda locks its movements. So you can easily Giga for damage redutction + heals, petal dance to the side and whip him with the boosted auto to stop it from escaping/keeping you at max HV range.
I'd say it's pretty easy to beat in 1v1 and even more so if you have a competent teammate, ideally a Defender/CCer/blissey
Honestly Sylveon is a strong characters but it feels like pre-nerf gengar, absurd as a pubstomper, falls off once people know how to play.
I have yet to meet a Mystical Fire sylveon so I can't tell you how that is