Two of my friends owned Hero Honda motorcycles. One being splendour and other passion plus.
One had bajaj discover and one honda shine, where in I had Bajaj Pulsar. They used them for a period of 8+ years while me and my bajaj friend had to sell our bikes in 4-5 years and I was surprised when the hero honda and honda guys told me the maintenance charge they paid against me. It was almost half of what I used to pay. Also the mileage their bikes gave was very high in comparison to bajaj bikes.
So I would say Hero or Honda is the best when compared to maintenance and mileage. Hope it helps.