All 3 Apple branded cases... If you are thinking of buying any of the 3 I'd recommend the battery case first. If you are not into the battery case then get the leather case from Apple.
The leather case feels much better than the last few iterations, especially the new button design. With the older leather cases, the button part of the case always wore down and made the button area flat and sometimes hard to press! These new leather cases not only look good, but they feel good in the hand. ;)
I don't really like the silicone case, it feels much more slippery compared to the iPhone 6/6s cases. It almost feels like the case has baby powder on it or something. If you have ever tried to bring back a deck of cards by sprinkling baby powder on them, then that is what this case feels like, it brings it back to life but too slippery.
Also, if you are wanting a case that makes the phone less slippery, then I would not recommend any of these options to help with that. The iPhone 7 is the most "un-slippery" iPhone since the iPhone 5s flat side iPhone's.
I am not really a case person, but I need a case for winter weather, so....
Smart battery case ($100); http://amzn.to/2dTpHPV
Leather case ($45); http://amzn.to/2dJwkYW
Silicon case; ($35) http://amzn.to/2daw2nu