So how does this work? If he uses Charge, does he get that +2 to the free close combat ACTION he receives from Charge, or does he make another close combat ATTACK with has the +2?

Maestro is in his second click: Maestro is given a Power Action, which he uses to enable Charge. He moves five squares, and then makes a Close Combat Action, which succeeds, and deals 5 damage. Then he uses the free Close Combat ATTACK given by Gamma-Saturated SP (because Maestro was given a Power Action) to make another attacks, which also succeeds, so that at one turn Maestro dishes out two attacks making a total of 10 clicks worth of damage?

Or are there three parts to Gamma-Saturated? So that you can either use Super Strength, Quake, or make a close combat attack with a +2 for attack?

Basically his special power is make an attack to get +2 attack as long as you're not using any other power except for Super Strength, so it doesn't work with Charge or Flurry.

Charge and The SP both require their own power action to activate, that's where you're running into trouble.

StormX is correct.

No, as StormX and Quebster pointed out, for the Maestro's Special Power to work like you outlined it would have to be worded like this "When The Maestro is given a Power Action etc."

His Special Power requires a Power Action of it's own to activate, it doesn't kick in automatically whenever he takes one.

For a good example of the different wording look at the Parasite's (or Super Adaptoid) Special Powers Attack Drain and Defense Drain

Very Nice SP. Hope to get a Maestro.

Thanks,