Tons of people complaining about iOS 6 issues after upgrading. I personally have not experienced any problems with either of my devices, but then again, I didn't do the upgrade the usual way. By that I mean I didn't download the upgrade to install it on top of the already iOS 5.1.1 I had. Instead, I did this below. I posted this on the Apple forums:
Guys I might have a solution to all your problems.
It is always best to install a new OS from scratch. Doing an "upgrade" is not always the best thing to do and this is what I have learned over the years when updating my iPhone and iPad:
1. Back up ALL your stuff to your Mac or PC (documents, photos, etc).
2. Reset the iPad or iPhone. Chose the option to delete everything.
A complete, factory reset.
3. Once the device resets and the OS comes back then do the upgrade to iOS6.
That is how I did it and I have not had a single issue with WIFi, battery life or anything anywhere near close to what's being reported in this forum.
Please let me know if this worked for you as well. It did for me.