I rode with my uncle, he was on a volpe, me on a 520. his bike was noodly with the bags on - too much frame flex. he never really got all the shimmies sorted out.

the 520 is a tank. it's heavy, and great at carrying loads. the bar ends take about an hour to get used to. i replaced the crankset with a MTB rig, as many people do. i love it.