Been coming to singapore for the last 2 years, had one customer, came to Japan in equivalent amount of time and Japan won. I had 3x the customers coming from Japan, it might have been a better network upon landing, but in general the reception I had was better.
I now live in Japan full time.
I'll echo other replies and say more mature market and it's what I like to call a source of money rather than an aggregator.
Singapore's main benefit is being a "hub". If you have access to the direct sources of money though, it's a hard justification (By that I mean more mature markets in east asia that might not speak english)
I just came back from Singapore a few days ago and my assessment of the market is still the same. I talked to enough companies there to see it still doesn't make sense for us to be there yet. In general, I also feel like I can make more of a difference in Japan than SG (everyone speaks english but there aren't as many resources and companies are really conservative when it comes to buying software)