I had Avon Storm 3DXM ( or something like that) on the the Orange K13 I P/x'd last week, liked them.
I've had Avon, Pirelli , Michelin on that, thought I'd try the Metzeler as I like them on the sports bike, and they also won the MCN SportsTtourer tyre shootout.
But i think they're all pretty good, ( except Bridgestone) , with subtle differences that suit some, not others.
Ability to heat up quickly on cooler Autumn to Spring days , and damp road handling , as the K gets used more under those conditions for me.
Hot sunny days, the Sports bike comes out.