Warframe or Path of Exile

Definitely Warframe. You will never run out of things to do, I've got almost 2000 hours in it and I'm not even close to 100%. New content every month or two. It's action packed, the community is great, you can customize the gameplay to your liking. Digital Extremes is one of the best devs/publishers currently, they listen to the community, work hard to deliver us great, exciting and original content and most of all they are awesome people. The community keeps increasing and going over 100k concurrent players.
Path of Exile is boring. It's the genre's fault. Diablo style gameplay is boring in the first place. No matter what you do in it, it has such visuals that everything seems exactly the same. Cosmetics are barely making any difference and at the end you are stuck spamming the same aoe spell all the time, or just run through dungeons with some aura type ability that kills everything. There is no sense of excitement and it doesn't feel rewarding. You either have to put no effort in it, or it's too difficult to enjoy. Hence the 20k people playing only. Those are hardcore fans of this genre and they somehow enjoy it. I also did 10 years ago when there were no other games to play.