I personally prefer the 'non-traditional' crispy thin kaya toast for its wafer-like crunchy texture.
I cannot recall if they charge extra for butter with their kaya toast but the interesting thing is that they would cut it into thin slices and place it in a bowl of ice water to keep it cold and ensure that it keeps its form and does not melt completely when it is served. A lovely touch but my gripe is that the thin stripe of butter was so small that it was as thin as (and if not thinner) than the thin toast itself and left me thoroughly dissatisfied.
I can't help but feel that I'm paying more for the old school atmosphere than for the food itself, seeing how they seem to 'stinge' on their ingredients...