These can be difficult to do right and be successful. They will throw you off more than a regular interview will having been there.
About three years ago I was had an interview with someone from an energy drink/fitness company at a restaurant. Looking back, getting a cup of coffee probably wasn't the best idea. A lot of people that are heavy into fitness aren't exactly into coffee so that made a rather bad impression. I just didn't know it at the time but was one thing that cost me the opportunity.
The interview was also at about 8:00 AM if I remember right so I wasn't quite awake either which didn't help any. Early morning interviews for me have either been the absolute best or the absolute worst. There really isn't any in between on those interviews.
There are a lot of things that have to come together to be successful in an interview. You need to be prepared ahead of time for most questions that will be asked. Try to be prepared for the unexpected question also, it will happen. Do you think that I was expecting a question about certain things bothering me at the interview for the job I'm working at? If I remember right my answer was "if it does I guess I'll get over it". Needless to say, I was successful and have been working there for over two years now.