Lowest common denominator of saving game information

Hello. I've read through many great topics on saving game files using UserPrefs, or saving to a file from Application.dataPath.

I have a game that will be on iPhone, Android, and PC/Mac. The information to be saved for a player is not vast, but it's also not trivial where I could simply store a few values in UserPrefs (which seems to be a universal solution). Also, I'm reading in these forums that UserPrefs is not very efficient to access in iOs devices.

Has anyone encountered this situation of multi-platform support for persisting non-nominal values? I could detect platform and save values differently based on that, but if there's a better way, I'm definitely interested in knowing.

Thanks.