Holy heck, how do you review Captain America?
The first thing that should be said is that FFG respected the character enough to make him formidable. It's been two and a half years and twenty-six heroes later, and Cap is still top tier. He's not infallible, and he doesn't has a magical secondary deck, but he has a powerful set of abilities that require meaningful yet reasonable costs.
His entire persona is really on point, but if I were to take up a small quibble, it would be that Cap really should have a 4 REC. He's just an unrelenting machine, and this is the sole area where I feel FFG dropped the ball. It's not a dealbreaker, but it's hanging out in the corner like Hamlet's ghost.
The only other issue I have is that Cap's ability to get his shield is exclusively a setup ability. This is a product of time and playtesting, and I think that if Cap were re-released today, it would be an alter-ego ability rather than a setup ability.
This is the route they have taken with all current heroes that have a signature upgrade (Thor, Hawkeye, Nova) so I am of the opinion that Cap is just a victim of the time in which he was created.
However, his Alter-Ego ability is tailored to Leadership decks (kind of a 'duh' situation there) and his Hero ability is a perfect, thematic balance of cost to benefit. Cap's 2/2/2 still stands out as formidable years later, and his shield provides him with both an extra DEF and Retaliate, which is unprecedented to this day. It actually makes it hard to play his Shield Toss, since it returns the shield to your hand. But then you remember that he has two unrestricted resource generators, and the Shield Toss is going to deal 4 damage to as many enemies as cards you discarded. The shield will be back out before the end of the turn, and thank goodness because that 3 DEF matters. It matters a whole lot more when one of the two Shield Block cards is in your hand, doing a Spidey Backflip to prevent all damage for zero cost.
Then there is Heroic Strike which is a reverse Tackle that deals three more damage. Not to mention Captain America's Helmet, Cap's 'Get Out of Jail Free' card.
Let us also not forget those two unrestricted resource generators; Super-Soldier Serum. For one more than a Web-Shooter, Cap gets a permanent source of might resources every turn, and he has two of them! Sure, they're not Wilds, but they have no restrictions on what they can be used for, and they are permanent upgrades.
Cap is a lot like Spidey, in that their hero kit is straightforward and easy to grasp once you know the basics of how to play. What separates Cap is that he has minion control, better thwart and permanent resource generators. They are solid compliments to one another, but Cap is the more versatile hero of the two.