XF2 is still officially in a pre-release alpha status and is unsupported, so it's not ready for use on live sites, yet (well, apart from this one
).
At minimum we'd recommend waiting until public beta (soon) or release candidate or ideally stable.
It is going to be simple to upgrade later, yes, but due to the brand new code base, any styles and add-ons you use in XF1 will not be compatible with XF2.