The Ice Ferret's not all bad. I'd gladly take a D over the Viper A, unless the terrain was so choppy that I'd take a Viper C over an Ice Ferret D. But, the Viper starts from a much better place, and on an ultra fast mech jets are nearly always a welcome addition, so no one ever really makes too much fuss. As a 40 tonner in a world of Clan heavy and assualt mechs with ER PPCs, you can never be too moble, I don't think.