LXi, this is very important: Please don't take the term "hack" out of context. This is NOT overclocking or operating over spec.
Much rather, hacking here means overcoming the natural stupidity of Windows drivers (which only have dumb presets like 60,75,85Hz) to take full advantage of the hardware--without necessarily violating its specifications. It's as if Windows underclocked your Celeron667 to 600MHz because it only likes 100MHz increments, and you forced tho stupid thing back to 666, or 666.6667MHz.
If the Samsung officially does 69Hz, that's exactly its maximum, just like 67Hz is Sony's maximum within spec. If you don't mind damaging it, you may very well "overclock" your Samsung to 70+ Hz, but its real refreshrate @2048x1536 is just 2Hz above the Sony. (Which BTW is clever enough to block any such "overclocked" modes.)