I don't have enough Electrum for an upped rainbow, so I've been trying other stuff. I found that rainbow relied heavily on Life quants (emphatic, mutate, firefly) and time quanta (draw more cards so you aren't killed) but in an unupped deck it's too hard to play well. If your mark is Life you need Time, and if your mark is Time you need Life. Not to mention the rainbow also needs Bonewall and Graveyard to get started. Too many factors. No wonder you go Aether with it. One day when I have 1 million electrum I'll try some of these fully upped decks out. =)