Yeah, I agree with you. should be safe enough but nothing to write home about.
There seems to be a lot of brands in japan though that are not cheap as chips like the arun and look quite decent, I'll try to look at a few of them once i get there. there are around $500 so certainly not wallmart quality (or maybe wallmart quality for 5 times as much :-p )

About buying used, Japan is not known for people buying second hand stuff (I personally like to)

It could be a good or bad thing though, bad thing because maybe i can't find any second hand bike to buy, or maybe good because if there is it would be affordabe due to lack of interest..
It'll probably be more a combination of both.