The obvious comparison to including this card is if you had 3 First Aid cards. This is definitely the better value. For 1 card, you can accomplish what it takes 3 cards in a non-protection deck to do. Furthermore, because using First Aid requires 3 cards, as opposed to one for Med Team, it costs 6 effective resources (3 to pay for each of them and 3 for the cards themselves) to heal 6 total damage vs. 4 for this one. I haven't played Protection much but I'm going to be trying it out again soon with a Thor deck and am eager to see how this fits in with it.
Uses (3 medical counters). (Enters play with 3 counters. When those are gone, discard this card.)
Action: Exhaust Med Team and remove 1 medical counter from it → heal 2 damage from a friendly character.
Any time I see talk about this card, I tend to only see comparisons to things like First Aid, which is fair, but it also misses a hugely important fact about this card. It can also be used to heal allies. In something like a Drax deck it can be extremely powerful when combined with Mantis for instance. Just a single Med Team combined with Mantis can generate 24 healing over the course of 9 turns, giving you a much needed long term healing effect for him. Basically any time that you would benefit from being able to keep using an ally, this card can keep them up for several more turns