we have just bought one too and have found the following
* city mode isn't brilliant as it seems to change gear later than you would do in a manual, but it can be tricked into changing earlier by backing off the throttle abit
* gear changes up are better if you back off the throttle a bit, makes no difference going down though as the engine blips automatically
* in the mode that uses the gearstick or paddles, the car will change down anyway, so in theory you only need to chage up
* I found the manual somewhat confusing at first and had to drive it for a week to then go back to the manual to have an idea what it trying to tell me.
* once a bit more used to it, it does work really well, just watch out for jumping into a standard car and eg trying to go into reverse without using the clutch, easily done
great fun once you've got the hang of it
HTH