Imo the benefits would be smoother (only one gpu), better minimum frame rates, less power draw, a 'tad' cooler running (seems funny to mention this as a plus point but it just shows how hot the x2 can run!

), and dx11.
In terms of raw power then it doesn't 'beat' the x2 though there isn't much in it at all. As I'm sure you're well aware, it's not about maximum frame rates. If you're mobo supports sli then you could add another later.
I hadn't thought of the 295 but that is certainly an option though it doesn't have dx11; though would a single 470 carry enough muscle to put out high enough fps with tessellation on? Tbh I doubt it, at least on some of the games we've seen so far.