with only 5 links these specters are pretty nice, it's outdamaging my storm mages which are 6-linked and 1 gem level higher (lvl 19 gems are annoyingly rare), tooltip dps and PoB are both fucking useless and super inaccurate for specters though, in actual play one can solo a t15 rare in a few seconds and has some flashy aoe abilities since it's a "miniboss" mob type.
83 spirit is still too expensive to run more than 1 though, you only need one to trigger their innate bleed and use their aoe attacks for clear though. right now I run 7 storm mages, 2 skeletal warriors, 1 immortal cleric with brutus' brain, ravenous swarm aura, and for my specter I've been experimenting and these seem pretty good