Warframe is a fantastic game. If you ever wanted to be a space ninja slaughtering thousands of genetically engineered aliens in the milky way, hundreds at a time, with any variant of weaponry you could imagine, and some you may not be able to, this is for you.
One bad thing to say, which is why I wouldn't give this game 5*s, is it's incredibly difficult to get into. There is little to no tutorials in the game, and your best source of information is the wiki, which is not linked to in any way at all in the game. There is no in game help, you are very much left on your own unless you play with someone who's played the game before / is completely up to date with what's happening in the game.
The amount of time / effort you have to put into the game to get to a point where you can kill nearly anything with little effort is pretty high, the game is a grindfest, but some people enjoy that, myself included. If you want everything in the game at your fingertips after 5-6 hours of playing, you're going to be dissapointed, unless you spend ridiculous amounts of irl money on the game, which I would not recommend at all, especially not to new players.
Having said that, there is no need to pay money to get all the meaningful content in the game, there are only a few cosmetics that are locked to only the real money currency, and you can trade for that without spending a penny on the game. It just takes time.
That said, the amount of effort DE have been into the game, with constant content updates is incredible. Some bugs not being fixed after several years of use is a bit of a pain, but the content included is incredible.