great article written by Gareth Scott -

Things to consider when recruiting heroes:

Are they PvP top dogs?
- Consider getting heroes that will give you an edge in Player vs. Player tournament fights. Oftentimes, alternative uniforms play a part in unlocking a character's full potential. Examples of these characters are Quicksilver (Blue Costume), Emma Frost (Phoenix Five), Phoenix (White Crown), Psylocke, Captain Britain, War Machine (Iron Patriot), Magneto, Rescue, Union Jack, X-23, Wolverine (Brown-and-Tan) among many others.

Are they needed to unlock Spec Ops epic boss?
- The needed deployment heroes are usually composed of a previous PvP Tournament reward (in the next chapter, it should be Shatterstar), a new 90 CP hero, and a generally underused character.

Do they unlock premium missions?
- If your primary goal is to fully master the chapters, earn its rewards and unlock the premium missions, you may want to consider getting Hulk, Spider-Man, Wolverine, War Machine, Phoenix, Human Torch, Thor, Dr. Strange, Luke Cage, Captain America, Mr. Fantastic, Gambit and Scarlet Witch.

Do they unlock story epic bosses?
- Epic bosses are unlocked after all mission events are accomplished. These fights give the player a chance to win rare Agent gear. For this, you may need Black Cat (S1 2.3), Spider-Man (S1 3.5 and 7.3), Storm (S1 4.4), Wolverine (S1 5.3), Luke Cage (S1 6.3), Invisible Woman/Thing/Rogue (S1 9.4), Spider-Woman (S1 10.4), Phoenix (S1 11.3), Kitty Pryde (S1 12.2), Psylocke/Union Jack/Black Knight (S2 1.4), Rogue/Scarlet Witch/Spider-Woman (S2 1.6).

I am a new player. Who should I get?
- I say complete the roster of cheaper heroes before moving on to the higher tiers (90, 135 and 200). They may not provide as much utility as the more expensive characters, but they sure boost your PvP bonus stats at a dirt cheap price. Also, they help unlock future chapters that require an "X" amount of heroes.

Should I recruit 200 CP heroes, are they worth it?
- If you have the CPs to spend on them, why not? You never know if or when they are coming back to the store: Mockingbird, Emma Frost, Magik, Ghost Rider, Valkyrie, Havok, Hank Pym, Vision, Rescue, Wonder Man and Daimon Hellstrom. These heroes, however, are not required in any deployment, heroic battle, incursion, epic boss or premium mission events at the time of this writing.