Hello. Yes, I have worked for interac for about 5 years. 

Its one of the better companies to work for though its not perfect. The pay is ok, but youll have lots of free time to find extra part time work, if your free and single though its more than enough to live on.

I live in Kawasaki and work in Tokyo. Most of the full time work (interac) is in Yokohama and the smaller cities. Tokyo and Kawasaki are mainly part time. I work in Junior High Schools which is mainly full time.  The first time I cam to Japan (2004) I chose Tokyo/Yokohama as I didnt want to be to cut off from western life and wanted to be at the centre of things. I worked for a different company back then. Tokyo/Yokohama/Kawasaki are for all intents and purposes the same. If you want big city lights, mainy foriegn friends from your home country and other western countries aswell as Japanese the you want to head to a big city Tokyo, Yokohama Kawasaki and Osaka have large foriegn communites. In these places youll be alright for finding lots of stuff from home if you need it. Other obs are available in these places too. If you want a blend of city life with a little more relaxed then you could try smaller cities like Nagoya, Hiroshima, Fukoaka.. Kyoto is very old style Japanese as well but has a sizable foriegn community. If you want a hardcore Japanese experience then youll want to hit a small town or rural area. This will be more difficult, you wont have many foriegn friends and homesickness can be a problem. Youll have to be tough and embrace some Japanese ways to stick it out. Alost everybody Ive met whose done that has much a better level of Japanese than us city dwellers.  Perhaps if your unsure a year in Tokyo/Yokohama or Osaka would be a good starting point then if you want to move out to somewhere quieter or more rural you can ask interac. They are always happy to oblige. In some rural areas you will need to drive though. 

Good luck with your interview. If you have any specific questions feel free to ask.