I thought at the moment, LFS treats all gearboxes like a H-Shifter? i.e. that's how they're simulated (gear->neutral->gear)?
Either way, I think i'm faster at shifting with the H-shifter, as it's using the manual clutch (which I can kick faster than the auto-clutch, at least in the road cars). However, braking/downshifting is usually slower, cause you're lacking a 3rd foot.