kit lens for kit lens?

[mastertrinity]

i have a sony 18-70mm kit lens (the first one out) now apperently sony are releasing a new 18-70mm with a smooth autofocus motor and so the focus should be nice and quiet, is it worth gettint the new one our should i just buy a tamron 17-50mm or similiar?

 

[heidfirst]

the new kit lens is an 18-55mm & IQ looks noticeably better on the 1 test that I've seen so far.

As to what/whether you buy that will depend upon why you feel a need to change at all - do you want it because it will be quieter (the Tamron won't be), have a larger aperture for lower light/less DoF, better IQ etc. ...?

 

[mastertrinity]

this is my requirements:
slightly quieter
much better AF performance
sharp images
nice detailed images
and preferably large aperture of f2.8 because i like using my DOF techniques however this isnt major.

 

[heidfirst]

quieter - well the Tammy or Siggy 17-50/2.8s won't be much different as they are still screw drive.
AF performance with those should improve over the kit because of the larger aperture
All 3 look to improve IQ wise over the current kit.

I suspect that availability & pricing of the new Sony kit 18-55mm won't be good for a while & several of your wishes apart from the quieter are probably best served by the 2.8s.
It's up to you really to weigh things up & choose.