Well the EVO is an more advanced version compared to LE, It has more features, more USB Ports, more SATA ports and supports integrated 5.1 surround audio.
If they are both within 15$ Range, get the ASUS M5A97 EVO 2.0.
But if you won't use those extra features, they are basically based on the same chipsets, and will have similar performance.
Source:
http://www.asus.com/Motherboards/M5A97_EVO_R20/specifications/
http://www.asus.com/ca-en/Motherboards/M5A97_LE_R20/specifications/
-Bloc97