I am going to handle XML files for a project. I had earlier decided to use lxml but after reading the requirements, I think ElemenTree would be better for my purpose.
The XML files that have to be processed are:

Small in size. Typically < 10 KB. 
No namespaces.  
Simple XML structure.

Given the small XML size, memory is not an issue. My only concern is fast parsing.
What should I go with? Mostly I have seen people recommend lxml, but given my parsing requirements, do I really stand to benefit from it or would ElementTree serve my purpose better?
lxml is basically a superset of ElementTree so you could start with ElementTree and then if you have performance or functionality issues then you could change to lxml.
Performance issues can only be studied by you using your own data,
Which Python XML library should I use?