My Japan wifi experience was: amazing speeds, 20 hours a day, completely unusable for 4 hours a day. Fortunately there was an ethernet port - far more valuable to me than wifi.
Yeah, before I went to Japan my "assumption" was that every square inch of the place was wired. Internet everywhere. All I'd ever seen was pictures of that one busy street in Tokyo with all the lights and glitz.
This was in Onoda, and we were staying in what I heard was "the only" western style hotel. If I recall it was a wired connection only, and the entire service would go down periodically, pretty much daily. I'd have to go to the front desk and say "internet down. no internet. can please fix?" or something of that nature and hope they would understand and go back into the back and reset it.
It was funny because they would recognize every westerner on the trip by face and hand each of us our correct room key when we came back to the hotel without a word, just a smile and a nod.
Sigh. That was a good trip, I hope to go back sometime. Very nice people and a beautiful country. Very memorable, especially the visit to Hiroshima and the museum there. I'd never felt quite that awkward before, as a US citizen in the Hiroshima museum.