I have Owl Eyes and I play Nova-Firefly. To be honest it's not that super powerful... it costs as much as a Firefly Queen to place, and it costs 2 Air to snipe a creature... taking up all the Air quanta I get from my Mark.

The 5 damage per turn is nice, but because of the summoning/sniping costs and there being only 1 copy of the card, you can't rely on it for your creature control, you still have to use Thunderstorm/Freeze/Reverse Time.

If there were more card draw and/or tutoring effects, then rares would be a lot more useful.