What performance can I expect from an Intel NUC?

[KHg8m3r]

Here's some comparable hardware, Gigabyte Brix boxes:
http://www.newegg.com/Product/Product.aspx?Item=N82E16856164012 Has an i7-4770R w/ Iris graphics
http://www.newegg.com/Product/Product.aspx?Item=N82E16856164011 Has an i5-4570R w/ Iris graphics

They're not low power CPUs, and have high clock speeds, so they should be powerful enough to run most games that don't require overclocking (am I right?)