the a6000 is straight up successor the the now discontinued Nex 6.
Sony have been pretty clear that they're dropping the 'nex' label, and using alpha for all the a-mount and e-mount cameras.
I bought a nex6 3 weeks ago. I'm not PO'd though - why get annoyed that a newer model has come out - it always happens, just a question of when. I figure buy the most suitable model available when the timing works for me (ie I have the money) not wait until the next model... because a year later its outdated too
It's not as thought the nex6 is any less capable than it was a week ago. Just there's something even shinier
I use my a900 in the studio, a700 for travel, and now nex6 for family/walkaround. Sure the a6000 an improvement (fastest AF on any interchangeable lens camera, I think I read) but the nex6 was available when I needed it, and was affordable. Not sure I'd have been able to afford a newly release a6000 for a while longer...