It's good to see Tamron putting their support behind the Sony NEX system and whilst they have gone for what is obviously the most commercially safe lens they could have released it's still good to see a third party company offer an autofocus lens for the system.
Obviously this lens will suffer from optical compromises due to it's design but the new 18-270mm lens Tamron have out is very acceptable considering the huge zoom range so providing this lens is a new design and not a variant of the existing SLR version then there's potential for it to offer surprising image quality, if it can combine some of the technology of the 18-270mm in a slightly less ambitious design there's no reason why it couldn't offer acceptable performance and best the overpriced Sony 18-200mm.
There is speculation that the Sony branded 18-200mm is made by Tamron anyway so this lens should offer at least equal IQ and hopefully will be significantly less expensive!
It's also a nice touch that the lens is offered in both black and silver finishes, something you could quite easily do too Sony!
Apparently the lens is available from this weekend in Japan so I look forward to seeing how it goes down!