If you compare it to Med Team, it's 1 resource cheaper, but you can't use it to affect your allies' hit points. However, its usability isn't limited if you are at full HP. Both save/restore up to 6 HP.

Compared to the likes of Desperate Defense or Never Back Down it doesn't give you any sort of kicker for not taking any damage, but do keep in mind it also doesn't thin out your hand during the villain phase when you use it, which I believe is a key point for them. And you can always stack it with defense events to make it easier or to ensure you won't take any damage!