The Nova Cat is a 4/6 movement 70 tonner. That means it should move equivalently to the speed of a Warhammer (64kph), while the Madcat and Vulture should be going upwards of 86kph.
Yeah, Vulture and Timber moves like a slugs now. They could use some speed boost.
From what i can tell, all the Mechs in game are slower than canon, but i've only checked a few of them.
The Nova Cat is a quick mech though, I like the one with the 2 PPC's and 4 LBL's, handles the heat fairly well.