In today's announcement about the Kinect-less Xbox One and the changes to Xbox Live, there was a small fine-print detail that many might have overlooked. Apparently  Games with Gold on Xbox One will work pretty much like PlayStation Plus on PS4, requiring an active subscription to play them.

**Free Games Offer: For paid Gold members only. On Xbox One, active Gold membership required to play free games you’ve downloaded. Must download titles during designated window. Kinect and/or hard drive required for some games.

Basically, if your Xbox Live Gold subscription lapses, you won't be able to play the games you downloaded until you resubscribe, which is exactly like Sony's competing offer (even if Games with Gold offers two games for Xbox One instead of PlayStation Plus' one, at least for now).

At the moment we're not aware of the reason behind the change in policy, and Microsoft did not explain it as part of the announcement. Most likely it has to do with the games offered for Xbox One being inevitably newer than the ones for Xbox 360, which possibly means that Microsoft will have to pay a higher fee to their publishers.

The inclusion of the Xbox One in the Games with Gold program is definitely good news, but this remains a rather relevant detail that should not be overlooked.

Update: Xbox Chief of Staff Aaaron Greenberg commented on Twitter apparently contradicting the fine print mentioned above, confirming that you can keep the games even after your subscription lapses.

Update 2: Greenberg doesn't seem to be so sure anymore about the issue, and promised to confirm it because there "seems to be confusion"

let me try to confirm, there seems to be confusion about that point.

Update 3: apparently the fine print was right, and Greenberg confirmed that you do need a subscription in order to play your free Games with Gold on Xbox One.

Confirmed with team on Xbox One you need to be Gold to play Free Games with Gold.