Espeon: 95.6% ivs, 2472CP and ZH-Psybeam
Worth max out for DEFENSE? 15A-14D-14S ~95.6% ivs.
He's at level 29 and will cost 65000 stardust to max out to level 34.5 with 2749 CP.
According to Gamepress ZH-Psybeam is the second best moveset for defense ranked as B, but anyone has powered or faced a Espeon with this move? worth or is a waste of dust?.

Answers
I would personally see Espeon's best use as an attacker. I would say this as its stats are high for attack but not so much for HP/def. It's only really worth powering up therefore if it has future sight. It's CP caps off a little to low to get high placement in gyms if you were to use it as a defender. It's outranked by Dragonite, Rhydon, gyarados and Snorlax.
P.S My Espeon got this same move set and I definitely won't be powering it up.
It's ATT makes up for its low HP and def. Coupled with the lack of double weakness that other high CP defenders are cursed with it does better than players would expect. Run some simulations and check them out compared to other popular mons.
It's CP is a tiny bit low though, honestly I didn't even think about that since it's not an issue around here. I think I recall you stated there is only two gyms in your area, maybe it would bring some good variety to your local scene:)
Yeah, I think for all these glass cannons, the lower stamina stat is very apparent...
I just fought one and letting loose an Arcanine Fireblast, took more than 1/2 it's health I think...
Defenders need HP more than anything else and a Chansey is a bigger annoyance IMO than any glass cannons since they'd be knocked out before hurting you enough...
In fairness to Espeon it has 20 percent more STA than Alakazam (the definitive glass cannon) and a killer multi bar stab move that hits as hard as single bar moves from some other mons with its huge ATT . That extra HP on def could mean an extra shot of charge move.
Not too fair to compare a a glass cannon to blissey, or anything to blissey really. When saying the poster should power it up, it's already at lvl 29 with near perfect IVs. There's not a whole lot of mons to power up defender wise of the gen 2 lineup but this is one of them considering the circumstances. Gotta spend that dust on something new...but yeah it's just my opinion.