For me, i just want to save the trouble.

Prior using the KIS, i have to,

periodically visit my friend,

plug out the hard disk from my laptop,

let him scan using paid version anti malware while chit-chatting with him,

plug back the hdd into the laptop.

That is my histroy for a person who concern about the computer security, but unwilling to pay RM 33 per year because at that time it represents xx% of my monthly allowance.

When i got my laptop in 2007, i only know about scanning the incoming media like USB pen drive. Until my friend explain the need of the internet threats and manage my own laptop's security properly, only then i willing to pay for the KIS. 

I say KIS is sufficient for me for primary use. For those who perfer other AV, i say internet security is sufficient. Some AV comes with the total protection features that can only perform better than the disk cleanup. I prefer use the tuneup trial. it is best for me in term for maintaining the computer.