Positive:
Not only is WarframeCompanion super convenient feature wise, letting you look at your inventory, craft items, look up information about the game, interact with your in-game companions, deploy and collect extractors and more... but WarframeCompanion provides an extremely clean and responsive interface to do so.
I'm not kidding, WarframeCompanion is *super* responsive. Steam, Playstation, and Xbox should all be incredibly ashamed for daring to put their apps on the same platform as this one. You can tell from this alone that this company cares about the game and it's user base.
WarframeCompanion also lets you log in and out of accounts across different platforms with ease, have a Ps4, or Pc account like me? Just log out and click a button and it'll switch right on over!(For pc, you will have to provide your password).
Cons:
For some versions of the game you'll have to reopen the game after using WarframeCompanion , as the game won't save until you relaunch it. This hasn't caused me any strife, and WarframeCompanion warns you prior.