While Michael was printed in Edge of the Earth, he actually seems like he was (at least partially) designed to work with one of the Scarlet Key investigators: Charlie Kane.
He's not bad in other investigators, see the other reviews for that, but he's well worth consideration in the politician. He gives two static boosts and soaks a ton, plus his first doesn't exhaust, so on turns where you're not fighting he just gives you a nice big bonus.
Additionally, because Charlie is limited to only level 0-2 non-Ally cards, it can be hard to find big pockets of damage for him. Events can be one way, but Michael Leigh offers another solution by turning your 2-damage .45 Thompson into 3-damage Lightning Gun. And using Bonnie Walsh, you can potentially get this bonus damage multiple times in a turn when fighting bosses.
While the 5 XP is certainly an investment, I think that players looking for a "fighter" archetype Charlie could seriously consider Michael.