For some reasons, QQ is now the most popular IM-ware in China. So i think you should try it yourself at first, to see if there is any problem of logging/connection. cuz as far as i know different regions have differe connection performance. If you have trouble connecting to QQ from where you live, then you'll probably have to try Skype (which is not so popular in china). Good luck anyway :)

If privacy and security are your concerns, then I will recommend Skype instead of QQ. Otherwise, just use whatever your friends use.

no problem to sing up or loggining :) but i dont want to download qq software, so i use miranda :) in miranda i can now only chatting in qq, msn, icq, aol at one time, but there are no video/voise, so i use skype too