MSI 7870 HAWK Or GTX 660/ti?

So I'm hoping to get a new graphics card after Christmas, I'm loving the 7870 Hawk edition for alot of reasons but I am unsure if it is the best option and would like some advice. Basically my 3 options are:

  1. Buy the MSI 7870 Hawk for £215
  2. Save some money and get the MSI GTX 660 Twin frozr for £160
  3. Wait a 2-3 months and get the MSI GTX 660ti Power edition for £250

Please bear in mind:

  • I am going to overclock it so compare overclocked performance not stock performance
  • I probably won't upgrade this card for a couple of years at least
  • My case has very good airflow for the graphics card
  • I am not going to crossfire/SLI
  • I play a huge range of games so I want general performance not game specific and I would rather have higher average frame rates than really high maximums and low minimums
  • I've heard people say the 660s don't scale as well when overclocking due to lower memory interface (192-bit) than the 7870 (256-bit) but i'm not really sure how much this actually is an issue

As a side note: I kinda like the adaptive v-sync and Physx features so that's a bonus for the 660/660ti but is it actually any good and does it drain performance in any way?

I would suggest to save up and buy a 7950, it should be about the same price as a 660ti but will overclock a LOAD better. This is because nvidia is limiting how much the chip is able to be oc'd. Even though the 660ti PE from msi still advertises tripple overvolting, it cannot be overvolted still.

The 7950 will also last you a while longer with tiltles like star citizen and crysis 3 coming out soon.

Which 7950 would you say is better the Sapphire vapor-x OC or the MSI twin frozr 3 OC V2? They are both exactly the same price (£259.99).