As above stated there is more of everything and needs to be done faster. The hard part in my opinion is being smooth. Banging through gears, and hitting apexes are not to hard but getting through consecutive corners with all that much more going on is where the challenge comes from. If you get to the high levels of shifter karting like S2 S1 it becomes that much more important. I would say start in TAG then once you feel confident enough move to shifter kart.