Guzzi's Le Mans was a great bike in its day, but until Dr John Wittner came along it never quite fulfilled its promise. On race tracks, especially in endurance races, it lived in the shadow of the older V7 Sport while Ducati and Laverda built on earlier success, and the Japanese continued their rise to dominance.
So what's going on today? Guzzi Le Mans are seen as robust, successful racers across the world. This years 4 Hours of Spa was won by a Le Mans, as was last years - different teams with different bike too - while Ducati propped up the mid-field. It seems you can now run these monster twins at 1100cc and (relatively) sky-high revs, making them unbeatable ard relatively affordable. Modern metallurgy is clearly a wonderful thing