I never failed to reach my friend in china via global sms (tried 135~,137~,136~,138~...).
However, sometimes I can not get my friend's reply. Someone said that only 全球通 can send global sms which is not yet verified. If you have frequent contact with your friends in China, my suggestions are:
1> ask your friends to send online sms which is free for Singtel and $0.1 for M1 (charged on you; u should subscribe), which are normally limited to either 10 or 20 sms/day.
2> using IM software such as QQ from Tencent.
3> use MSN Robut which used to be my favorite. Just add one robot's msn account and send sms by following some coding mechanism. Usu. you have to register with the help of a friend in China. RMB0.1/sms. 1 extra free with every 10 sent.