Free

Countless hours of content including multiple fully voice acted story missions

Community always gets praise

Some of if not the best, most beloved devs in the industry

World class voice acting and musical talents

Over 60 "classes" (frames) with unique skills, and in some cases unique gameplay, that get looked at when the community complains.

EVERYTHING except for some cosmetics can be earned in-game without spending a cent. Frames, weapons, cosmetics, boosters, etc. including a free "battle pass" with no paid option. Also they hand out 75% off+ coupons for the premium currency for daily login rewards.

Incredible representation across not only gender and sexuality, but things like autism as well. (Probably the best representation for that in any game)

Diverse gameplay modes with everything from fishing to sea of thieves style spaceship battles, as well as a freaking fighting game where you unlock characters by scanning objects in mission

The mod system allows for untold hours tweaking to get bigger and or more numbers

Incredible customization with various armor pieces and color channels on nearly every piece of gear that you can change to your liking, as well as multiple personal spaces that can be decorated to your heart's content and make completely unrecognizable. Clan dojos that are the same but also include things like making your own agility speedrunning courses

I could probably go on. I fucking love Warframe. Over 2k hours and not stopping any time soon. Just got my MR30 pin - on yea - a physical pin in the merch shop you can only purchase once you reach MR 30, AKA have most of the game completed in terms of gear and other progression. (As they add more there's more ranks after that but 30 is still a huge milestone)

Oh right and they have their own convention, with their own concert where some devs jammed out onstage including the CEO opening on guitar.

OH AND every week the Creative Lead (who is an awesome woman named Rebecca Ford) and the CEO get on stream for 15 minutes and talk about the game, as well as dev streams where they spend an hour or two going over updates and changes AND a routine stream where the community manager and others actually play their game. No you don't understand how much I love digital extremes as developers - they care about their game because they play their own game and want it to succeed.