The smaller mutual and challenger banks are still leading the majors on home loan customer satisfaction, if the latest findings from Roy Morgan's survey of home loan customers are any guide. Or, to put it in starker terms, out of the eleven largest home loan banks, the Big Four have the lowest levels of satisfied home loan customers. Only 80 per cent of home loan customers with the Big Four banks said they were  either "very satisfied" or "fairly satisfied" with their bank.Topping the table was ME Bank, with 92.8 per cent of its home loan customers telling Roy Morgan they were satisfied with their bank, closely followed by ING Direct (92.7 per cent). These two banks were well clear of their competitors, with the closest being Bank SA (88.7 per cent) and Bendigo Bank (87.6 per cent).As for overall customer satisfaction over the year to September 2015, some of the smaller banks showed the largest gains. The Bank of Melbourne increased satisfaction by 5.8 per cent points over the year (to 87 per cent), and Teachers Mutual was up 5.2 per cent points (and remains overall market leader on 95.3 per cent). Bank SA increased by 4.3 per cent points (to 87.7 per cent) and Bendigo Bank was up by two per cent points (to 89.9 per cent ). What was more telling, though, was that even after a sustained period of low mortgage rates, three of the Big Four banks (ANZ, CBA and NAB) have home loan customer satisfaction levels that are still below those of their non-home loan customers. Only Westpac has home loan customers that are more satisfied than their other customers (80.8 per cent compared to 79.8 per cent). This has underlined how important getting the right mortgage strategy has become in a very crowded market. "With signs beginning to emerge that home loan rates will rise, it will be of critical importance to track how mortgage customers feel about their bank as it is likely to adversely impact on key metrics such as satisfaction and advocacy," said Norman Morris, industry communications director at Roy Morgan Research."We have seen in the past that if increases in home loan rates are given a great deal of adverse publicity, then a decline in customer satisfaction inevitably follows."