“Python 2.x versus Python 3.x”: this is by now an old question. In the eyes of some people Python 2 is here to stay, and in the eyes of others Python has long been 3 only.
PyPy’s own position is that PyPy will support Python 2.7 forever—the RPython language in which PyPy is written is a subset of 2.7, and we have no plan to upgrade that. But at the same time, we want to support 3.x. This is particularly true now: a relatively recent development is that Python 3.5 seems to attract more and more people. The “switch” to Python 3.x might be starting to happen.