As the original owner of a 2004 Super 9 (all original - no mods) I would have to vote for the liquid cooled model. There's nothing like zinging around town on a cool Summer (or Fall...or Spring) night 48+mph on the great handling Super 9. Excellent front and rear disc brakes also! 13,000km on mine.
I love it so much, I bought a new Kymco, and then could not part with the Super 9.
Wil B.
Broadview, IL
'04 Guzzi Ambassador
'91 Nighthawk
'04 Kymco Super 9
'10 Kymco Yager 200 gt