Against Chicago, they looked like crap.
Against Seattle they looked good, but everybody is shutting down Seattle's offense. Even the Bears held them to 3 for a half, when their offense looked like JV backups.
KC was a good game, but KC's been pretty mediocre this year.
SF - Facing a QB who throws at receivers' feet will really make a defense look good.

On the other hand, Raji has looked really good. Mathews has been all over the place. Perry and Daniels are getting after the QB. Shields and the rookies are covering well and making plays. There haven't been many glaring WTF plays, and Dom simplifying the calls probably helped that.

So there's reason for optimism, but enough unknowns that we can't say how good they are for a while.