Yeah the i5 doesn't differ too much from the i3 outside of TurboBoost, but TurboBoost is worth it.
Also for $100 less you can get a similar Asus with 4 cell, no HDMI, and i3 2330m (just a shade slower) LINK
It's a picky point, but another small advantage of the i5 is a SLIGHTLY faster GPU.
Both have the HD3000, but the i5 Graphics will generally be clocked just under 10% faster for the it 24xx and just under 20% faster for the i5 25xx.
Mind you, they are still not great, but if grabbing it for Wow and other stuff, that is one more thing to consider when weighing the value of that $50.