I have an iPhone 4 on Verizon Wireless and I got iOS 7 the minute it was available. Honestly, I wish I hadn't. Not that iOS 7 is horrible, it's different and that isn't a bad thing. But I have noticed that there is more lag now than I had before and I really believe most of the UI and apps are designed to optimally work on iPhone 5, 5C, and 5S displays and not the smaller 4 or 4S displays. My battery doesn't last nearly as long as it did with 6.1.3 and I've done all the recommendations I've read the last few days about optimizing the battery performance. Also, if you use "non-Apple certified" charging cables they will stop working with iOS 7. I had to dig out my original Apple cables to get my phone to be able to charge correctly.
Overall, I think iOS 7 is okay, but wish I had a newer device to run it on.