After watching both Avengers 1 + 2 and Guardians of the Galaxy I realised that the heroes and characters in Guardians of the Galaxy and the Avengers have the same characteristics and can be compared to each other in many ways.
Gamora Vs Black Widow
Gamora is known as a "Galaxy Class Killer" or "The Deadliest Woman in the Galaxy" due to her skills and being a bad-ass assassin. Black Widow is known as "Black Widow" due to her ruthless behaviour and how she can carry out jobs other people won't. Both had pretty bad childhoods, with Gamora's parents being killed in front of her and her race becoming extinct thanks to Thanos, and then Thanos cybernetically changed her to make her into a weapon. Which can definitely be compared to Black Widow's extensive training in the Red Room, for she too was made into a weapon.
The real question is.. who's more of a badass?
Peter Quill (Starlord) VS Captain America
Star Lord and Captain America are each others counterparts because they are both leaders. Peter is the leader of the Guardians of the Galaxy and Captain America is the leader of the Avengers. They can be compared by their traits, both are incredibly brave but they can also be compared because they're both out of touch with modern day earth. Cap is influence a lot by the 40's and Peter is influenced a lot by the 80's. Cap is out of touch with modern day planet Earth and so would Peter if he came back, not as much as Cap but he'd still be pretty out of touch.
Groot VS Hulk
Groot and Hulk are each others counterparts because they both have amazing strength and are considered "the muscle" of both teams. Hulk can get kinda out of control but so can Groot (like in the prison scene where he was screaming with rocket on his back, or when he took out like six of those guards on Ronan's ship). Hulk and Groot are also the most intimidating looking in both teams and both of them don't say much." "I AM GROOT"
Which do you prefer?
Drax VS Thor
I have nothing.... they both speak fancily? I don't know?
Which fancy speaker is the best?
Yondu VS Hawkeye
Arrows and stuff?
Which Arrow user person is your favourite?
Rocket Racoon Vs Iron Man (Tony Stark)
Rocket and Tony are the mechanics of the two teams. We see this when Rocket can builds bombs from old ship parts and Tony can make his suits, but these guys are the wise crackers and the funny guys in both teams too. They're also the artillery guys because they're into their weapons and using them.
Which mechanic do you prefer?
To conclude a lot of the guys on the Avengers and the Guardians have the same traits and characteristics and please please god let them team up for Infinity War because it would be awesome to see them spark off each other and team up together to take down Thanos!