In response to your quesitons, July....
Nova honored all of my requests, but it took some time. I was first assigned to Shimizu Nova (in Shizuoka prefecture) and requested to move to Yokohama. It took a few months, but I eventually got transferred to Yokohama. Of the two, the smaller town was nicer and much friendlier. I would recommend not requesting a large city. As for days off, a lot of that can be worked out by trading with your coworkers. I was able to switch my days off, but, once again, it took time. Keep in mind, days off will always be consecutive and you won't get Sat & Sun because those are the busiest days when students want to come in. I was also able to switch to the early shift (which I preferred). The trick is to put your requests in way ahead of time. I did find that it was easy to get the vacation time I wanted as long as I did it in advance. If you're in good with your coworkers they'll even help you with some shift swaps.
The nearest Nova office to where I'm from (Seattle) is San Francisco (not close). Fortunately, the interviewer scheduled a trip to Seattle to interview me and some other applicants and I was able to do the interview here in town. I think I remember they showed a video and then did a brief interview. It really wasn't that big a deal. It is true that Nova will hire just about any native English speaker who has a B.A. On the other hand, I also interviewed with Geos - the interview took three days and included practice lessons and grammar tests, however I didn't like the teaching methods Geos uses.
Nova does have its share of slackers, but I met all kinds among my coworkers at Nova. Definately no shortage of interesting characters and all very nice. I really enjoyed getting to know and socializing with my coworkers.
I think I did my interview in November, got my answer a month or two later and arrived in Japan in March. Once you get your answer the time goes quickly because there are a lot of preparations to make (paperwork, visas, passport, buying cloths, etc.) before your departure.
The main thing is that if you go into it expecting it to suck, it will. I went into it expecting an adventure and thoroughly enjoyed my time in Japan. Although after teaching at Nova for 15 months, I was definitely ready for a change.