I rarely ever use a preset exactly as-is, but it's a great starting point for many of the more complicated vsti's
normally I hate ALL the effects and turn them off so I can add my own, and I usually tweak it very carefully to suit my articulation needs
actually being able to utilize presets fully is all about understanding what the damned knobs do
edit: agree with proto that peach, toad, and triforce are now EVERYWHERE and it's awesome