For mine, Rainbow Six Siege is the best shooter going at the moment, and while it launched to a general mood of ambivalence last November, Ubisoft has reported a significant increase in active players since then.
Ubisoft recently provided some figures to IGN, and the increase looks positive: that site was told that the "daily player total is higher today than it was when we first shipped the game nine months ago". Meanwhile, daily active users has increased by 40%, with the biggest increase coinciding with the recent launch of the Operation Skull Rain update.
Here's the (rather vague but still illuminating) graph for you:
Creative director Xavier Marquis added that "we invest in Rainbow Six Siege as we would invest in our own home - we check the pipes, the foundations and everything else, [and] that's because we are here to stay."
Those figures are all platforms – so Xbox One and PS4 is included – but it's a good sign. In addition to three major content updates since launch, Ubisoft launched a Starter Edition with a different monetisation model.