I have had 6 79's, 2-70's and 4-50's:
7970 WF, ok silent@idle, aggressive when it hits 60c, medium clocker@1150MHz but developed a fault within days-returned.
His Ice-Q 7950, annoying grating noise@idle, not bad on the noise under load, rear venting too-tremendous clocker@1200MHz-returned as I'm anal about noise.
MSI 7970 OC another tremendous clocker@1200MHz+/1850MHz on the memory but died out of the blue-gutted but full refund as they are hard to get now-seriously bad noise levels but it was sat on top of the fantastic AC Extreme.
XFX 7950 seriously cheap@£200 inc Never Settle bundle-Flawed cooler, poor clocker@1100MHz max voltage through Trixx(meant to be voltage locked), it's now getting passed on to a friend.
Another Ice-Q, monster clocker@1250MHz+/1650MHz His iTurbo full core/vram voltage support-this one doesn't have the grating problem-guessing His sorted it out.
MSI TFIII bought the other day, no diode issue, fan works as it should, 1170MHz/1600MHz+(stopped pushing as it doesn't need to go that far could go further on the vram), but AB doesn't apply voltage even though AB reports it as applied, so Trixx to the rescue again, but no vram voltage option-yet(upcoming newer Trixx is supposed to have vram voltage adjustment support).
For
gaming@1080p, although the 7970 was fantastic and I was very happy with it, the price difference you pay is only noticeable from your wallets pov.
If it runs on a 70, it runs just as good on a 50 when they are both oc'ed, the only way I would say go 70 is for high res gaming or bench marking-where the little extra oomph(the vram clocks considerably higher due to higher grade chips, so at least there's some justification) will see you good.
So what ones my overall best recommendation?
It can only be this one:
1 x
HIS HD 7950 IceQ BOOST 3072MB GDDR5 PCI-Express Graphics Card (H795QC3G2M) with Crysis 3 & Bioshock PC Games £239.99
Just found out it's on offer and I never noticed, but it's time for tommy to just be content now.