I bought Honda activa(not 3G) 3 years back and I never got mileage beyond 38 kmpl. The bike is vibrating a lot and it is not at all comfortable.
I am experiencing back pain and stopped using it unless very required. The maintenance of the bike is very high and as ususal Honda spares are costly than others. Better to go for Hero and TVS products. Please look for the telescopic suspensions if you want to keep your spine safe.