Did I come off as snarky or hostile there? If so sorry, I'll shut up.
Haha, the vacuum comment seemed a little snarky, but I can be that way too. Just trying to get my point across. Way too many times I've tried to help people understand why some Pokemon work and why others don't, but it frequently turns into 'why do you have my favourite Pokemon', or a discussion in theorymon instead of actual experience.
Umbreon is my favourite eeveelution and third favourite Pokemon.
Umbreon is fucking terrible.
I actually looked him up on Veekun a few days ago to try and find a niche for him. His stats, movepool, ability, and arguably typing are all worse than Cresselia. The only thing I can think of is STAB Foul Play + Swagger or something.
I'm in the same boat. I love Umby, but it's a really bad Pokemon. Of course I also have soft spots for Beedrill, and Cacturne too.. among others..