Let's not give Miller more credit than he's due -- the 2010 budget surplus was the result of unique circumstances, mostly beyond the city's control. Miller balanced the city's operating budget every year, as the city is required to do by law, but he was never able to balance things without using one-time funds like reserve money or provincial gifts.
The difference between Miller and Ford is that Miller believed that the only way for the city to get on stable financial footing was for the province to upload some of the costs downloaded on the city during the Harris years, whereas Ford believes the city can achieve a sustainable year-to-year operating budget purely through cuts to waste.