Probably one of the best Free-To-Play Titles mankind have seen to this date

1. insane graphics, developers put a lot of effort into the game's design
   
2. most Items are grindable, so you don't have to pay to get something( even though you can bypass some MR restrictions)
   
3. variety: you can play whatever mission you like and don't have to be linear, if you don't want to.
   
4. cinematics: later in the game you'll encounter multiple cinematic quests which add a lot of content,context and story to the game

1. very grindy: you may grind multiple days and then a few AND have to wait between 10 minutes to 2 and a half days in order to craft certain items in the foundry
   
2. Quite empty PVP servers: PVP servers I join from where I live are most of the time empty with barely anyone ever joining
   
3. pay for certain content: for some content(mostly cosmetics and PRIME VAULTED warframes) you have to pay if you want them, but, since the Vaulted frames are mostly PRIME warframes, which normally just are standard warframes with upped Health and another Polarized Modslot, you don't really need to have them.
   
4. flawed beginning: if you are about to start playing the game now, you might think the beginning is way to simple and doesn't really provide any means to continue playing, but this will change on the later planets, especially as soon as you start to unlock Sorties and Kuva Missions.

all in all I'd say that most other Free to play Games should take a piece of how DIGITAL EXTREMES handles their game, which after about 5 years runs even stronger than ever, and even though it is flawed, especially for newcomers, it quite well can keep up with nowadays AAA games (yes, i have a sideview over to you, Destiny(2))
score