A swear word is about as meaningful as an angry emoticon.
Not in this forum, you'll be lucky if you don't get an infraction for that in that particular context.
Regardless, I do find it amusing how people love to recommend the card that is in their sig as the best bang for the buck because THEY purchased it.
The GPU game is way too close for there to be a clear winner in a replacement for a 4870x2. What it comes down to is power consumption, and if you can get a card for the same price as a used 4870x2 that can match its performance, and can provide a little DX11 eye candy if needed, why not go for that? It will pay for itself in power savings over its lifetime without a doubt. Trust me I know first hand how quickly GPUs can add up in power costs. Running a bitcoin mining operation with just 6 GPUs shot my bill up over $150 in a month. You're talking about a 4 GPU setup there. Yes you wont be running it 24/7, but if you can save even $30 a month by side stepping to a more efficient piece of tech, I'd say jump on it!
As far as a GTX 560, I would never recommend it. Anything lower than a 560 Ti just wont cut it for very long @ 1080p or higher. I know, I have 4 TIs. Even in SLI they aren't great but I will admit they are ROCK solid for SLI stability compared to AMD. I will admit I wish I had at least sprung for a 570 since they can Tri-SLI, or wish I would've held onto my GTX 580 for quad sli. I do love my 6970 Quad-fire setup, but I really want to put my 3dvision monitors to use... I've yet to even test 3dvision as of yet =\.