I've owned them all in your list Ducati, Guzzi, BMW, all three big Japanese and currently a Triumph '08 (built in England) . If you have a Duc twin or Guzzi V twin they are pretty simple (assuming you have some knowledge of how stuff works) , my BMW was an older air cooled, other than crazy Bing carbs it was pretty straight forward. All the Japanese had good/bad habits. The triumph just runs like a champ, 1050 triple is a nice engine that so far just wants oil changes and filters.
Unless you start buying V4 panigals, and road legal superbikes that need a laptop and software they all have the same level of need IMO.
The same guys that kick HD , kick at Italians bikes with nothing more than coffee shop gossip to fall back on.