Okay, well, I've noticed a lot of FG decks in the Top 50 have Anubis in them. Since Anubis is usually used to protect two specific creatures, Elite Otyugh and Fallen Druid, would running one or two Quintessence be more viable than running one or two Anubis?
The amount of Time quantum used in the standard Rainbow deck, at least one that uses Hourglasses and/or unupgraded Sundials, is quite large, and Anubis doesn't help this. However, the amount of Aether quantum used is very little, as it's usually only used on TUs, or the occasional Ulitherid.
I was just messing around with different FG decks in the trainer, and I found that Quintessence is a tad more useful than Anubis, and much easier to play, since I don't have to wait to play Anubis, then make it Immortal, and then play my other creatures and make them Immortal, too. Quintessence makes the deck faster, and saves two turns.