I rode a Bianchi DISS for four years. Never had any issues with the bb, headset, hubs, spokes... People pick things apart, a lot of people break stuff themselves and deflect blame. Bianchi's make a great singlespeed and back it up if something fails. Just keep in mind that very very few of the thousands and thousands of people who've ridden these happily and with no problems at all are going to log on to say the bike is doing exactly what they'd hoped. They're too busy riding them.
Plus, they have great resale value.
Some people bash Bianchi because after they've agonized and scrimped and saved and maxed their cards building their SS/FX dream bikes, Pista, SASS, MUSS, SUSS, and San Jose riders are having just as much fun and going just as fast. At about one-fourth the cost.
They're good bikes is all.