Well I have green, yellow, orange, and blue lines.
It really depends on area, if you travel a lot in Malaysia, blue one have the best coverage among these telco.
But the internet speed is just so so only, not considered as high speed but still can surf normally.
Other telco might have higher internet speed but their coverage really cannot compared with blue line. Especially when you go to East Malaysia, many other telco don't have service.
Orange telco is the worst although they have cheaper plan, I already cut two of my orange lines. Now left green, yellow and blue. And blue is the best for me because I travel a lot.