Is it Safe and What benefits will i get if I update my iPhone 4S iOS 6.1.3 to 7.1.2?

The 4S 64gb was bought on 4th November 2011 and recently giving serious battery drainage issues other than that the phone is absolutely perfect.

I just want that new look of the new os

Will I have any problems with my Wi-Fi connections after the update? And will it improve my phones performance and battery life?

It has made no differancd to my iphone what so ever, the battery is okay, for the batter issue I would suggest buying a new battery they arnt that expensive look on eBay.
My Wi-Fi is also very good with the phone with the new update, all seems perfect and just the same but with the new look and style of the OS!