legion implies multiple people, as does a guild name, 'is' is not proper when plural
"They is the best raiding guild in wow"
"They are the best raiding guild in wow"
"BL is the best raiding guild in wow"
"BL are the best raiding guild in wow"
so on...
while they may not be the best overall, currently the best is what people always argue about.
that they are the best right now, has brought up discussions of previous tiers?
and it remains to be seen, they are the best for HoF, not MV, and those are the same tier.
TES will be the tie breaker whether they are the best this tier.
also for that guy who keeps mentioning method (what is a method?) <-sarcasm ofc.
http://www.mmo-champion.com/content/...an-World-First
Method was not first for MV, no use commenting on them here, and if you meant overall even previous tiers.
they were not the best there either.
hence the (who are they) comment.