In the old days of all air-cooled bikes, people on a budget bought single cylinders, and wealthier people often bought twins for more power, or more weight and less vibration to make the bike more comfortable on long trips. The V-twins like a Harley or Indian or Vincent or Crocker were narrow for dirt road ruts, but the back cylinder got hotter and shortened the engine life. Later, Triumph had a parallel twin so both cylinders were in the wind to increase the engine life, and they could have higher compression with higher reliability from less overheating.
BMW has the boxer twin for a lower center of gravity for comfort, but in a tight corner or a crash the heads can more easily hit the ground. The Moto Guzzis had the air-cooled heads higher (transverse V-twin), for more cornering clearance, and the heads are in the wind for more air cooling, to last longer than the Indian or Harley V-twin. Indians had V-twins first, and Harley copied them, but some tiny companies that went bankrupt had V-twins before either of them, with looser patent laws at the time, so there is no patent for the V-twin design. Harley tried to patent their V-twin sound and failed.
Moto Guzzis are nice bikes- the Italian company takes the time and money to make them look and sound good and corner well, but they are small niche bikes with a higher price new or used, and slower and heavier compared to similar Japanese sport-tourers, more on the touring end of the scale, but with a different and to some better look and sound and feel. I think they are too heavy and too expensive for most beginners.
Here is a newer black Griso 1100:
Since they are quite reliable, you can sometimes find an old one like this for cheap that still runs well:
Honda had a liquid cooled Moto Guzzi copy for awhile, but most people said it was too top-heavy and it did not sell for long: