I loved Japan, although I was only down in Yokosuka long enough to have a few drinks before walking aboard the boat.
On the plus side for gaijin life in no particular order...
-chance to live overseas in a part of the world than doesn't end in 'stan, and where you can easily travel to other kick-ass locales
-already on-scene in an AOR that is only becoming more and more interesting
-COLA
-gaijin upgrade means that you can roll out to a bar and hook up while putting in less effort than it takes to bust ass after taco day on the boat
-when the overseas screening is actually applied, you get some great Sailors
-soju on the train to tokyo
-a constant re-affirmation that despite what some people say, the US is far, far, far from being the most racist country in the world. This might sound weird, but as a white dude, I found it very valuable to get to see a small glimpse of life as a racial minority
Negatives
-very restrictive liberty policies for Sailors and Officers alike, which constrict every time someone does something stupid
-you may spend your entire time working AOR specific issues, and never deploy to the 'stan or Iraq. Obviously, still doing good work, but can be a little demoralizing.
-there is an extra degree of difficulty for everything, from getting your car registered to moving off base, and unlike Olympic diving, there aren't any extra points for it
-having to cut off a finger if you dishonor your command
For the pilots and 'FOs out there, I recommend CAG FIVE highly. The 'wing is very tight, you get a great understanding of other platform's capabilities as a result and the port calls are epic.
