I've been watching and papertrading the STW the last few weeks, and my impressions are that it is more thin and volitile than the Nikkei contracts, probably due to its .10 tick size. For example, it doesn't appear to "respect" S/R areas created by swing highs and lows quite as well. Also, when it gets booking in one direction, it often doesn't provide nice reaction pullbacks for safe trend-following entries... it just keeps moving in one direction much farther than you would expect. It seems to reward the momentum style trader cause it can get off and running, but this is not my style (where do you place your stop if you enter like that?). I like the hours/margin/tick value though; I just need to figure out how to tame that beast.
I fully realize it has nothing on the HSI though for volitility... Kiwi probably gets drowsy trading STW.