Tillers
 

I've noticed that most large transport category aircraft are taxied using tillers. I would like to know
1. why this design is prefered to the 'conventional' rudder steering found in smaller aircraft.
2. which is the largest aircraft that is steered using rudder pedals?
3. if rudder inputs have any effect on aircraft fitted with tillers.
Thank you for your replies in advance
Capt. manuvar