Many MMOs feature combat with poor contact physics, luckily Warframe does not have this issue as combat feels responsive. Add on top of this the amount of guns in the game as well as the great melee weapons and there is plenty for every type of play-style.
Environment as well as character graphics are stunning. Every level has its own lighting (and it's quite randomized. You get to play at night, with sun, during a storm, with hot lights or cold ones etc..).