Should be nice and hackable...
It look like this will be a very good choice for those of us who like to root their phones...
Sony (yes, Sony!) are actually pretty good to the Android community, making it easy to get into and hack the phones, and supplying lots of good information. Unlike certain others, including Samsung who are really missing a trick.
Having a Qualcomm CPU goes along with that, Qualcomm are also very pro-hacking, whereas the International version of the S3 has an Exynos CPU which is not well documented.
After Sonys chequered (solid black?) past in these things it's very good to see them being more open.