I've had one person (so far) mention building what the party needs. This rule set doesn't have healers or the like. While you CAN do various sorts of super powered spies and information gatherers, they may not be all that helpful. Then again, when you need one, they can be nice to have.

That being said, build what you want to play. A Brick/Tank is always handy, as is a Projector. But damage is pretty much the same for everyone, modified by their Rank and Multiplier power. Actual powers tend to do pretty much the same damage, but with varying Fantastic effects. Of course, there are always exceptions.  This makes the choice of character a matter of personal preference and style, for the most part.

I've build a half dozen differing characters to get a feel for the rules and powers, and I've noticed a few short cuts and benefits. I'll note them below, in case they might help someone.

Basically, the chance to hit and the chance not to hit use the same attribute for the same type of attack. The are broken down into 4 categories:
Melee for Melee, Agility for Physical Ranged (Including most Elemental Powers), Logic (TK and telepathy, including Control powers, Control powers  (Grab, Push, Suffocation, etc) that aren't Telekinetic or Telepathic (Elemental mostly) and Magic powers (but Magic doesn't apply here).

The multiplier powers (Accuracy, Brilliance, Discipline, and Mighty) boost damage and out of combat rolls, but not to hit or defense rolls.

While you're likely to only train one attribute (two, possibly, if you use elemental powers) this needn't leave you lacking in Defense. The powers Brawling, Evasion, Integrity and Wisdom let you (at the price of one power slot) get twice the protection from one attribute by having it protect against either both physical combat modes or both mental combat modes. This is a lot cheaper than training multiple attributes up purely for defense.

There is one temporary power available. By "Temporary" I mean something you can get from the military and turn in later to clear the power slot.

While they pass out weapons to boost your multipliers early on (by rank 2 or 3 they no longer help) they don't do the same for armor. You may spend a slot of a Flak Jacket, with the High Tech limitation. It will confer 1 level of Sturdy, and NOT add to any innate Sturdy you might have.

Truthfully, buying actually Sturdy 1 would be more effective, likely. However, TK and elemental powers have Defenses in the power set that you need to Rank up to acquire. This could serve as a stop gap until such time as you have acquired them. At that time you turn in the Flak Jacket, free up the power slot, and, probably, spend it on the defense in question. Or keep the Jacket if you want (and keep the power slot set aside for it).

If you absolutely have to be an officer or senior noncom, take your free Trait for your new rank as Extra Occupation: Leader

While a single leader type wouldn't be a bad idea, it's not necessary. Someone will be appointed/elected as a leader type purely for making calls as to when to use a team maneuver. Beyond that it shouldn't matter much. Tactics training won't be a factor here, most likely.

Power slots may be converted into trait slots, and the Surprising Power trait may be used to buy a power you don't have the Rank or Powerset for.

You must still have all prerequisites, however.

This will be handy with some power sets at rank 1. Super Speed, for instance, has a minimum rank of 2.

There may be the occasional Magic or Special Training power that you just have to have, such as a Telepath with Exorcism, or Do This All Day for a Focus driven self healing power.

This particular Trait is open to abuse. I will NOT let you buy a powerset entirely with this trait simply to earn a bonus power, for instance. If you're spending power slots to make Trait slots to buy a power set (as opposed to a single special power), I'll treat it as a new power set, and adjust your powers total to reflect it.