If you're planning to double up and go crossfire with the r9 270X than the 4GB of VRAM will help in the future. Otherwise, stick with the 2GB model as the 270X isn't the card you want at resolutions above 1080p for gaming. Considering you can get a 2GB Gigabyte GTX 270 for less than $200 and it's essentially the same card, that would be the best value for money if you're comfortable with overclocking (on this card just setting the sliders to max and hitting apply). If you're set on spending $250ish, the GTX 760 will be worth it over the 270X.