I use H-shifter and manual clutch with road cars. Now that I've practised it from christmas, I think I'm equally fast (or very close) to paddle shifting. On corners where there is downhill or little turn just before actual corner, I found it more difficult, because can't keep two hands on the wheel.

Quote from Greboth :

A g25 here as well. I use the cars lock for the wheel and it caused me troubles in the RWD cars at first but used to it now.

720 degrees turning felt horrible at first, but now I couldn't live without extra precision it gives

Quote from JJ72 :

Do you have auto clutch disabled?
Mind actually start to have problem staying in third gear (it sometimes wander to 1st), time to call up the warranty.

I'm having the same problem.

However, as for lap times with the G25 i am about the same using the clutch and H-shifter with no aids activated.