GPU Worth it?

[Thanatognomonic]

Hey guys, I've got a little problem
I've recently (within the past week) got the Radeon HD 7770 as part towards my budget build (which is limited to about £450 incl. OS)

My problem is that a friend of mine has recently told me of a GTX 660ti he's selling for only £100. I know this is a steal for the 660ti, since it's normally priced at around £170, but should I pay the extra £100 for the 660ti and go to Steam OS instead of windows or should I stick to the 7770?

I apologise in advance if my question is confusing, I actually had no idea on how to set it out.

 

[cin19]

I will recommend to test the Steam OS in your PC first to see how you feel it, like it or not, if you like it then get the 660ti with the Steam OS because the 660ti is much better than the HD7770. And also you can sale the HD7770 if you got the 660ti.

 

[Thanatognomonic]

I do have to ask, since I plan on getting a AMD FX-6300 would the 660ti be bottlenecked at all?

 

[cin19]

No.