Im gonna fill in some details about The Master chief (the details comes straight from the books, but they are part of the canon, so it do counts):
He have fought 207 ground engagements with the Covenant, all of them successfull.. he have recieved every recommendations in the UNSC exept the PoW medallion... and think about this.. in all those missions, he didnt have the armor that he has in the games (the Mjolnir armor he didnt get untill a few days before Reach fell)... also the enhancements and training have teached him to ignore wounds... for instance, during the fight on Halo and all the way back again to earth, he had burns, contusions, fractures and internal bleeding and the only sleep he had gotten the last week was unconsciousness brought on by his wounds, such extensive wounds would have put any human in state of shock and still he said he was fine and still kept on fighting as if he didnt have any wounds in the first place
Also with the enhancements he (and the other spartans) got when he was 14 years old.. he could run 55kph, lift 3 times his bodyweight and can see in the dark.. and his reaction time is 20 milliseconds, but also significantly faster in combat situations when his adrenaline is pumping... (these stats improved even more after he got the mjolnir armor, he can punch through concrete and jump over 3 meter high obstacles, he even can dodge bullets)
(NOTE: His powers was scaled down in the games so that they would not be too easy)
Im sure Samus is a great warrior as well even though i havent played the Metroid games... but i just have to hand it over that the chief would win