It depends on what your looking for. "Best City?" not sure about that. Here's my take---I'm from NY, but visit my step-children who live there quite often over the last 8 years & have even recently considered a move down there once:
Pros:
1) Well planned community--golf cart paths everywhere you want to go--very cool concept that I wish existed more places.
2) People seem to be very social, families come together a lot
3) Great place to raise kids--safe, good schools, very family oriented city
4) Beautiful area
5) From all my times visiting, I never had a problem with the traffic, though some people claim it's bad...I think...aside from rush hour normal congestion...it's nothing.
6) oh---this will show that I'm from NY...but wow, baggers at every checkout aisle in the grocery store.
Cons:
1) Even when coming from NY, the real estate market was quite over-priced in my eyes. Taxes are lower, yes, but homes cost a lot more than I thought they would. Go outside of Peachtree City...and homes lower.
2) If your kids aren't active (into sports), by the time they are a teenager, they will be very bored as there is little to do.
3) Restaurants--ok, coming from the NY area, I'm going to be a food snob

but really, there is little aside from chain restaurants here.
4) This is a Delta airline community....so the unstableness of what's happening with Delta has done some damage to several businesses I'm told---pilots have taken some pretty severe salary cuts. That might be good for home buying though? People might start selling at more reasonable prices.
5) Beautiful yes, but very boring to me. Atlanta is close, but not close enough. If your looking for simplicity in life though, you can see this as a bonus.
6) I found it to be a little Stepford-wives-ish & didn't think I would be happy there, but to be fair, I didn't spend that much time, so this is an impression.