Really pricey card. Two readies for 4ER is nothing spectacular, and every card that cost more than 2 should be worth considering. Another reason is that you probably don't play any other card in the same turn (or play something really cheap) which means this characters must be very good or you are on the edge on win. Whatmore they must be a Avenger and Guardian characters: in solo this is hard to make (because your hero can be only one of 2 characters). Multiplayer is not different story. You got the alliance cost yes, but there a still tons of better alternatives. Unfortunately Cosmic Alliance requiers really focus building so it's not worth including in any random deck. I see the situation when you got two characters for like 5 damage, but sometimes it's a win more situation, when you can spend more effectively cards and got better result.

Final rating (A-C) C Only for additional challagne, or when using specific build

In multiplayer it's like both players played Limitless Stamina which is a very highly regarded card. If you are playing an Avenger and a Guardian this is definitely worth considering even if it doesn't make the final cut.