Which one you prefer to use. Currently to be honest I use both but more prefer to Gmail. Yahoomail sometimes got problem to access I dont know why but gmail never give me any problem so far. What about you guy?

Gmail hands down. It has the best spam filter I have ever used. It is fast loading, can work easily with thunderbird, can use it as an ftp server to store files. The amound of storage is amazing, and grows the more you use it. GMAIL..... point.