I think the Scarabeo 500 is similar to my BV500 and uses the same, or similar, engine. The engine is a good'un and I generally really like the machine, BUT
the BV350's engine is, in my opinion, better than the 500. The 500 is a last generation design. The BV350 engine makes close to the same power, pushes the bike almost as fast and has much longer service intervals. The BV350 also has WAY more storage than my BV500.
If I was making the decision today between the BV350 and the BV500, I'd go with the 350.