Such rankings will be as skewed as they can get since the criteria used would probably be quite subjective.
Sample these past write-ups
1. Informal survey by Bankelele :
2. Purported professional survey :
3. A blogger's opinion :
From my experience, I vouch for StanChart, I&M and NIC. I can't seem to find some latest write-up on this topic, that seemed a bit up to date.
PS : StanChart screwed up their online banking experience in their recent upgrade. Some foreign banks are now totally missing from their system necessitating visits to the banking hall to effect any transfers 
Tony.