[Nyororin]

Unless you have serious time to kill, I can`t say that the bus from Tokyo to Osaka is a good way to go. It`s faster than regular trains, but a lot slower than the shinkansen. I took an express bus from Nagoya to Tokyo, and it literally took the entire day. (Okay, maybe not that bad, but it was a good 6 or 7 hour trip.) That may not sound like it`s killing a whole day, but really, it is. Unless you`re GREAT at sleeping on buses, or go on a night bus that happens to have beds..... You aren`t really going to feel like doing anything after a trip that long.

To compare, we also recently took the shinkansen to Tokyo - about an hour and a half. We sat down, ate our lunches, talked for a bit, then after playing for a little while on DS or PSP - we were there. It seemed almost *too* short.

I`ve also done the regular train with a 18-kippu to Tokyo one, and that was just too awful to consider doing again. 9 or 10 hours if you include changing trains, which you do VERY often on the regular lines. Ended up splurging and taking the shinkansen about half the way back because the thought of doing it again made me feel ill.
Then again, my husband apparently went all the way up to Hokkaido that way before we met... But he only rode the train for about 4 to 6 hours a day and stopped in a bunch of places along the way.

Buses do have a good point though - they are cheap, and are easy.
Their prices are comparable to regular trains. And they`re easier than trains if you just want to relax on your trip. The bus goes straight to the destination, no matter where it is, so you don`t have to think about changing trains. Once you`re on a bus, you can relax until they get there.