Definitely Widow. Once you get her sig level up, she kills opponent defensive abilities...strongly reduces Spidey evade, becomes hard(er) for defenders to parry her in war, and can basically nullify IM arc overload.
I think the only one worth using it on is Black Widow. BUT
1. Is she already ranked up or are you ranking her up immediately?
2. Are you planning on using her on your attack teams to deal with problematic foes like Spiderman and Electro?
If the answer to both questions is not "yes" then hold the awakening gem. Never awaken something you are not planning on using immediately. Immediately is like tonight, or maybe tomorrow. If you are planning to use her this weekend, wait to Friday night to awaken her.
This way if the situation changes between now and then, you won't regret using the gem. If you awaken something and then use it to do content you couldn't do otherwise or would be harder or more expensive to, then even if something better comes along its still not a wasted awakening. You still got valuable usage out of that gem. But awakening something to put on the shelf until you decide to use it is asking for trouble, unless you have a ton of awakening gems and they are going to start expiring.
Comments
1. Is she already ranked up or are you ranking her up immediately?
2. Are you planning on using her on your attack teams to deal with problematic foes like Spiderman and Electro?
If the answer to both questions is not "yes" then hold the awakening gem. Never awaken something you are not planning on using immediately. Immediately is like tonight, or maybe tomorrow. If you are planning to use her this weekend, wait to Friday night to awaken her.
This way if the situation changes between now and then, you won't regret using the gem. If you awaken something and then use it to do content you couldn't do otherwise or would be harder or more expensive to, then even if something better comes along its still not a wasted awakening. You still got valuable usage out of that gem. But awakening something to put on the shelf until you decide to use it is asking for trouble, unless you have a ton of awakening gems and they are going to start expiring.