I have the old one (the BDDI pedal), and I don't use any of the suggested presets. In particular, I find the SVT simulation pretty far from the real thing. They're nice as a starting point, but IMO one has to practice more than a bit to find the right sound.
My use of the SansAmp on stage is limited to solo parts (i.e. Fireball - I play in a DP tribute), while in studio I made some experiments by directly plugging the pedal into the mixer, and I must say it's a very nice toy...