>>37988484Espeon has great speed and SpA, a good movepool, an amazing ability, and generally outclasses other psychic types that aren't Alakazam.
Sylveon is and has always been one of the strongest offensively-oriented fairy types with huge SpA and Pixilate-boosted Hyper Voice, along with *okay* coverage moves and utility (including Wish/Protect as a RestTalk alternative for healing), and good defenses to make up for its low speed.
>>37988488Glaceon is mostly just outclassed by most other Ice type special attackers. It doesn't really bring anything unique to the table.