Choosing best XML parser library in C?

I am newbie on this website and also a newbie on linux !!!

I am planning to write an utility that needs to access a couple of configuration files written in XML.
I need to read and modify these files frequently.

I am looking forward to views/suggestions on following things:-

1) I am little confused about using expat or scew library or libxml2. (I need to program the utility in C)

2) I feel that DOM supporting parsers library will be convenient for my utility.

3) I need to deploy my utility on a MIPS h/w.

Thanks !!!