in my so many years of dealing (and of course using as well) with different local telcos, the best is Celcom

DiGi so far havent give me any headache, but when it comes to efficiency of coverage, billing, walk-in service/enquiries etc etc, Celcom is really simply the BEST.....

the most lousy? none other than stupid Maxis, and thank God me and my whole family (and plenty of friends, colleagues) already get rid of it......

totally unreliable and sucks all the way, somemore can extra charge by a lot!