Hi Nigel, I went from a
Hi Nigel, I went from a Sofrider (same as the Freerider except for the handlebars) to a Silvio 2.0 (a bit less aggressive than the Vendetta). I was well adapted to the Sofrider and my skills transferred right over to the Silvio. For a while it felt odd to be lying back so far but it wasn't really an issue. The Vendetta has a lower seat angle and a higher bottom bracket than the Silvio, so you may have a bit more trouble adapting -- but if you're fine on the Freerider I bet you'll be fine on the Vendetta.
As for how much quicker, I think we will have to wait and hear that from you!