I have been playing this game since forever, directly after beta as I recall. I will be reviewing Warframe in a pros and cons format.
Pros:
*Chill/Easy.
*Pretty cool looking characters and cosmetics.
*Satisfying.
*Will get you hooked up.
*Purchased currency (Called Platinum) can be farmed by selling items earned in game to other players (This is something amazing).

Cons:
*Unnecessary nerfs to some features quite often.
*Lack of endgame (biggest setback).
*Very bad PvP.
*Way too repetitive at some point.

I have developed a love hate relationship with this game. I say that as I am dying for endgame and challenging content, as well as the hope of a much better PvP system. Yet, I still hop on every once in a while to chill and slaughter masses of enemies with great fashion and fancy animations.