It would be easy to make arguments for both of these groups since both had their good points and their bad points. I will argue that the political machines were more successful.
The most important problem of the new urban environment, in human terms, was the poverty of the working class and the immigrants. The political machines did a great deal to help these people in very practical terms. The machines depended on this group for votes and, therefore, delivered benefits to them in the form of things city jobs and informal welfare services. By contrast, reformers often did things like educational programs that they thought were important but might not have seemed as relevant to the poor themselves.
Since the machines provided tangible benefits of the sorts needed by the poor, they were more successful in dealing with the new urban environment of this time period.