I have used this tactic several times, winning many tournaments.

(V) Riddler 47 Points
(V) Harley Quinn 42 Points
(V) Green Lantern (Unleashed) 165 Points OR (V) Green Lantern (Cosmic Justice) 145 Points OR (U) Green Lantern (Cosmic Justice) 151 Points
(V) SHIELD Medic 16 points
(E) SHIELD Medic 15 points
(U) Spiderman (Infinity Challenge) AKA Secret Wars Spiderman 116 Points

The experience levels of Riddler, Harley Quinn, and SHIELD Medics can be different to suit your needs but DO NOT modify Green Lantern or Spiderman. This team is best used for a 500 Point Team so you can add extra characters for Outwit and maybe some back up Perplexers.

Now, this is the formation they must be in...

R = Riddler

H = Harley Quinn

G = Green Lantern

S = Spiderman

M = SHIELD Medics

R G H (this in front)

M S M (this in back)

Now, Spiderman has an 18 defend, giving all of his buddies next to him an 18 defense, and if Green Lantern as Energy Shield, he has a 20 Defense! Really hard to beat. Also, Spiderman has his very own team ability as a Wild Card. Need an extra SHIELD agent? You got it! Need an extra Batman Enemy? You got it! He's got an 11 attack that can be shared easily to Harley Quinn OR Riddler if things get hairy.

The Perplex Ability of Harley and Riddler is good to have. They tend to keep it for a few clicks, which will be needed for Range, Attack, or Damage. Remember the new rule called the Rule of Three, so also keep in mind of the modification to damage SHIELD teammates can use and (if using GL) Ranged Combat Expert's Modification.

Lastly, The SHIELD Medics. They both can use Support AND SHIELD team ability. I recommend only using on SHIELD Medic if you plan on doing more damage, so that the other can heal when needed. So if you want to use 2 SHIELD Damage Modifications, use Spidey's WildCard team ability.

Green Lantern Corp is gonna get you out of hairy situations. He can carry everyone into or out of battle easily, especially since 2/3 of the GL's have Phasing on their first click!

Major Weakness:

Always keep this in mind if you are facing this team or if you are using this team. If someone gets a figure behind Green Lantern, Spiderman is in big trouble. If Spiderman is gone, you better have a backup plan. For example, anyone of the Kingdom Come can really stir up trouble for this team because of their HIGH damage values and HIGH attack values.

A way around this, though it may only be a temporary solution is Green Lantern's Telekinesis or Carry ability. Always protect your Spiderman.