They were not created by gods (the Valar can't really create new life), but just sent by them.
As the other Maiar, they were before the world existed.
'Dangerous!' cried Gandalf. 'And so am I, very dangerous: more dangerous than anything you will ever meet, unless you are brought alive before the seat of the Dark Lord.'
The question is if he'd use his powers.
Gandalf would be Nr1 no quastions asked about that
, he beated the balrog and thats no easy task to do,
and remember when the balrog took his sword and stroke at Gandalf?
Gandalf had like this (ever played Warcraft3 and used the Paladin?)
Divine Shild, and I guess he could more damege then the others
since he is a maya spirit thing, whatever, For the other guys, Aragorn or Borormir would be nr2, and then legolas or Gimli
Gandalf cannot just raise his staff and turn everyone else to ash. Even the Istari do not have such power. Lord of the Rings is NOT Dungeons and Dragons- nor is it Warcraft! You will note Gandalf never fireballs anyone or calls down lightning from the sky. As the Grey the most he did was destroy a bridge with magic, even as the White the most he did was cause a weapon to catch fire or blind some people.
In the Hobbit, Gandalf cannot even best a group of giant spiders- indeed, considers sacrificing himself to get the heroes out of the situation (and he would not have been sent back!). The Balrog, of course, Gandalf was very suited to fighting against, being resistant to much of the Balrog's natural advantages, like the fire and stuff, and having the Lore to know how to kill it. But in general battle? He uses a sword like everyone else, and the others are most likely better.
So get these ideas of a super-powerful Archmage out of your head. He uses his BRAINS, not super power- the trolls in the Hobbit he does not confront with magic, he tricks them.
Boromir was accounted to be the strongest warrior in the Fellowship.