WP7 currently doesn't support native code at all. There has been some speculation at my work that they will introduce it soon, but as far as I know, no C++ would run on it. It also has less multitasking ability than the original iPhone, from memory.
If you want Maratis on your phone, choose iOS or Android for now. If you want to create Maratis games for mobile and distribute, choose iOS. Android, as much as the devices can easily outperform iOS ones, is so fragmented, it is incredibly difficult to support all, even in terms of something so simple as screen resolution.