Happy accidents, Penicillin, Stainless Steel, Viagra and Vibe are all there in the best human kind has stumbled upon. The circuit which we now recognise as Vibe was originally designed to replicate a leslie rotary speaker and that's fairly obvious when you think about the tones however it offers soooo much more.
As with all things classic pedal circuits we tend to migrate towards the originals which players normally agree sound the best. With this mindset JAM Pedals created the Rotovibe Mk.2 and people all over the world agree this is one of the best recreations of the greatest vibe circuits from history such as the Shin-Ei Uni-vib.
The switch will push the circuit more towards vibrato or chorus tones but the vibe is always still the dominant sound. This often confuses players new to vibe as it sounds closer to a phaser, here you can use tonepedia to here the difference between the four different effect types!