I drive quite a few of them. The worst for 'jumping' is 2639. Its the Crimestoppers bus from NB. It was involved in an accident within the last year or so and apparently has not been the same since. And the heaters dont work either. 2680 was another jerker, but thankfully its gone to SS. I have driven two lately that blew my socks off. 2661 & 2662, both from NB. These buses used to operate the old NIR Suburban bus service along with 2663. This service was the forerunner to Centrelink. Well 2661 & 2662 are a scream. Smooth changes and fast acceleration, almost too fast! The addition of security screens would make this pair ideal for lates. I agree with you on the Ultras. Im beginning to prefer them to the Renowns. Although, my favourite will always be the N Type Tigers.