There's not a lot I can say about this movie that hasn't been said already by Derrick Ferguson Jack Badelaire and Mark Bousquet (who is also writing a series of character specific reactions) and a lot of others.
I thought Guardians was a clever move by Marvel Studios - it builds on elements introduced in The Avengers (Thanos and The Other) and Thor 2 (The Collector), and does so in a way that takes us beyond what we've seen previously and explores a whole new direction. The movie opens with the abduction of young Peter Quill from Earth and he's our point of view character in the story. That opening takes us from the familiar (Earth) and lets us explore the galaxy.
Chris Pratt in a lot of ways reminds me of Harrison Ford's Han Solo (and this probably makes Disney's Han Solo film that much harder). But Pratt's Quill is not the only character who we meet and develop a bond with. There is one scene that had both my daughters in tears, so much did they come to care about the characters.
Rocket Racoon and Groot are the Jay and Silent Bob of this movie and I would cheerfully plonk down my cash for a movie starring them.
Gamora is an interesting character, in spite of her messed up upbringing by Thanos, she is willing to betray him to do what is right. The movie offers her in direct contrast with her sister, Nebula.
Drax the Destroyer is a focused character and is literalism is played for laughs, but his partnership with the Guardians causes him to grow. Actually, that holds for all the characters, alone they couldn't achieve their individual goals but together they move beyond their limitations and become better and more effective in achieving their goals.
The Guardians are getting a major push by Marvel in the comics and appearances in Hulk and The Agents of SMASH and Ultimate Spider-Man animated cartoons.
I loved this movie.