Hi! I live in Tokyo.
Welll, one plus is that you’ll pretty much have the plane (and immigration, and transportation into Tokyo) to yourself!
The power outages hit different areas at different times. Most of Tokyo’s 23 wards are still exempt, but that could change at some point. Everyone is conserving energy, which means store lights are drastically reduced (many stores–even convenience stores–don’t even light up their outside signs, so you can’t tell whether they’re open or not), and most department stores have cut back hours of operation. Many free-standing stores aren’t open at all (not sure when regular operating hours will begin again).
Most of the trains that run through Tokyo have cut back on the number of trains running per day, and some simply stop service earlier. This means that crowds of people are commuting at very different times than usual. I don’t know what you plan to do in Tokyo, but you may want to check and make sure whoever/whatever you plan to meet/see is available/open.
Obviously the Fukushima plant is dead in the water, so energy conservation/fewer trains/shorter store operating hours/fewer shops open/rolling power outages can reasonably be expected to continue for the time being. TEPCO is working to open some of the less-damaged power stations, but Fukushima was a huge supplier, so it’s not going to be easy.
Oh yeah, have I mentioned that even HOSPITALS, if they happen to be in a designated power outage area, also lose their electricity? Unbelievable.
With aftershocks continuing, the concern over Fukushima, the daily radiation warnings, and for many, the 3-hour rolling power outages that occur several times weekly with very little prior notice (the electric company does try to avoid them when power supply exceeds demand, but they don’t know what they’ll need until a day or two ahead of time), the empty store shelves, the gas shortage AND the god-awful AdCouncil ads that run NONSTOP because few advertisers want to hawk their wares these days, life kinda sucks in Tokyo right now.
The bottom line, though, more important than these conveniences (which very few complain much about) is that given the horrific tragedy that’s hit eastern Japan, people aren’t in a very festive mood. There are still so many people unaccounted for, so many displaced, so many hurt and injured (and dying, even after rescue) that people just aren’t up to go out a-partyin’. Everyone knows someone who knows someone from up there. The death count goes up daily. There are still people who have yet to receive any assistance whatsoever–there is just no way to know where everyone is.
From what I’ve heard, the situation in western Japan is quite different. Of course they’re aware and concerned, but as western Japan operates on a different power line frequency, there’s no need for them to conserve energy for east Japan’s sake. The mood might be more festive out there.
You didn’t mention what you are coming to do, but inconvenience/safety issues aside, eastern Japan isn’t really in tourist mode right now. Many foreign expatriates have left. I guess what I’m suggesting is that if you have personal connections and friends/family you are wanting to see here, then that’s one thing. But if it’s for a nice visit to see Japan’s sites, I’d pick another time to come. It’s not a happy time in east Japan right now.