Some other reviews are calling this place a stepping stone, but this place nearly cost me a great job. During the interview process my current employer reached out to the sonic HR staff and did not get a response. I worked there for 6 years, and they can't even be bothered to return a phone call to confirm it.
Looks like everything else has been covered in other reviews; terrible compensation; no correlation between performance and advancement. Honestly, if you're proactive enough to read reviews of employers before applying - I guarantee you can do better.