Okay so I'm curious what everyone thinks. I've been given some hateful feedback about using Eos, but in all honesty I don't see anything wrong with using her. Her Whispering Dawn and Fey Illumination have helped out on numerous occasions and her Fey Covenant has saved my party's ass before I get that Selene can increase spell speed and skill speed, but if the dps buy FFXIV Gil need help then there is something wrong there. So tell me why it's bad to use her?
Eos is mainly for heavy healing parts of the fight. (adds of T11 &12, T13 while learning it) Selene helps push the phases with the speed boosts. Which helps out with less healing in pushing phases. Less healing is more MP. But when I see a sch use Eos, I only complain to myself and let them play their way. Cause I am only a black mage(Selene + Fey Glow= Love). I'll let people who actually play their job help others out. As long as people aren't dying you are doing your job.
If you're not comfortable using Selene then use Eos, however if your co-healer isn't too bad or you have confidence solo healing in dungeons she's a bit 'meh'. It's not that her skills aren't good but Eos isn't exactly FFXIV Gil helpful unless you are directly controlling her or the party is taking a shite load of damage. For example if i'm healing with a white mage i'm always going to use Selene. Eos's skills have a 2 minute CD and they don't stack together either. Her Whispering Dawn is only 1 minute long, however if it's popped at the wrong time it can be really annoying for tanks as it's the equivilent of a Medica II. I don't know your ilvl or your experience in the game so I can't judge it but unless your co-healer is really bad or you're in a low level (Selene's skills are useless unless your party is full casters til about 40, that spell speed buff isn't gonna do shit for a low level anyway) Eos isn't really going to help you. If you have double SCH, one of you has to use Eos or should rather because their buffs do not stack. Otherwise you should just use Selene most of the time to help the party kill things quicker.