Fortune got a hold of a report surveying smartphone software developers by William Powers, an Apple analyst at Robert W. Baird & Co. Powers surveyed 250 developers and found a lot of complaints about Android versus iOS. Among those developing for Android fragmentation was a "huge" problem for 24% and a "meaningful" problem for 33%.
There's no information in the Fortune article about any survey data on complaints by iOS developers. Would be interesting to know if any had problems with Apple's app store rules or procedures, for example.
Powers is an analyst who covers Apple stock, which he rates "outperform," so he's not completely an unbiased party.