I can't really comment on the coffee drinks because I HATE coffee

but I will say that not all Sonics are the same. While we were building our house, we got in the habit of getting the family size popcorn chicken because it was so easy to eat while working. Well, come to find out a Sonic out of town charges about 2-3 bucks cheaper for that same family size. And another one out of town I stopped at once didn't even offer the family size. Didn't know what I was talking about. I actually held on to my receipt from that cheaper one for a long time thinking that the next time I went to the one in our town, I'd show it to them and get it cheaper but I doubt they would do that..... and then the receipt faded so much I threw it away. My favorite at Sonic is the tator tots with cheese! AND the Vanilla Coke. I know other places have that drink but it's something about their styrofoam cups with the little bitty ice that makes it so good!
Oh! And remember when Sonic would hang those little plastic things on the side of your cup? The little plastic monkeys?? Boy, I'm sure dating myself now but that was a kick to us when we were little. Loved those little monkeys!