I've had Waze largely working fine on iPhone 5 with both of the first 2 betas of iOS 7. There is a new beta 3 out this morning for those who have access to it (an Apple Developer account). I'm not sure about this new 3rd beta, since I've had to roll my phone back to iOS 6.1 because of other critical apps that were not working...
Follow up: you can roll your iPhone back to the latest available version of iOS 6.1 for your phone (either 6.1.4 or 6.1.3 depending on your hardware) without jailbreaking the phone. You will, however, have to download the "restore" file separately from iTunes through your Apple Developer account (though they're also all over the Internet) and then install it to your phone the same way you installed the iOS 7 Beta, except selecting the iOS 6.1 file. The only caveat is that it cannot use any backups created with any of the iOS 7 betas, so you can only restore to the most recent backup that you took prior to installing the iOS 7 beta on your phone.
Wazing the Garden State... one jughandle at a time.
AM: New Jersey, LEVEL 5
AT&T iPhone 5 / iOS 7.1 / Waze 3.7.8