Help me decide! Great deals on 7870's but R9 270X looks good too

Alrighty, i need help from you guys to decide if i should get a 7870 or the newer R9 270X. I also need to get a need a new PSU of around 600-700 Watts. Im under a budget so i was looking forward to getting the card and a PSU this black friday week. Here are the rules/budget limitations.

Card cant cost more than 200$

A PSU under 70$

I just cant decide which one i should get because the 7870's are going dirty cheap because of the new R9 270X and ive seend them go to 160$ and it isnt even black friday week yet. But then the R9 270X is a stronger newer card that costs 200$... And im not entirely clear on this, will only the new generation R7-R9 graphics cards support Mantle? Or will Radeon 7000 series also have it?... Also if you guys know any good amazing deals or sites i should be watching for please tell me.

My system specs if needed:

MSI 970A-G46

16GB 1600MHZ RAM

PNY 2GB GT 430

FX-6100

Unknown 500 Watt PSU that i got with a 30$ case combo... And it didnt blow up for 3 years and thats why i want a definitely need to get a new one.

Keep in mind i have a GT430(fully OC) that does okay at games. But it sucks, but i cant blame it. Got it for 50$ and its a preety old card.

First of all, I have a 7870 in my system and it is very powerful. I can max out all older titles, but games like crysis 3 I do have to turn the settings down a bit to get into my fps comfort zone of about 45fps or higher. In my opinion, you should always go for the latest and greatest when upgrading. There is obviously a premium on these newer cards, and that should also be taken into consideration.

Note: If there is any way you can swing a card with more than 2gb of VRAM, that would be a good idea. I almost break the 2gb barrier playing crysis 2 with the high resolution texture packs and everything maxed out. It would be worth the investment i think.

As far as mantle goes, all GCN graphics cards will support it (that includes the 7000 series and the R7 and R9 series).

As far as the GPU goes for under $200, the 7870 is a fine choice, but wait for the black friday sales to see if you can pick it up cheaper or a better card like a 7950 or the R9-270x. P.S. As far as I can tell, the R9-270x is just a 7870 re-brand. Also, take the never settle bundle into consideration as well, the R-series doesn't have it yet, but it should be here soon. Whatever card you get, ASUS, MSI, EVGA, and GIGABYTE, are the brands to buy. Don't skimp on quality or you might have to pay return shipping :)

As far as the PSU goes, this 600w one from corsair on newegg for $70 looks fine. http://www.newegg.com/Product/Product.aspx?Item=N82E16817139028

The 7870 and the R 9270x is essentially the same card, with the same performance.