If you are a normal Linux user, then you'ļl be fine, and modern ARM plus support chips should be less power hungry than Atom and chipset, although Intel has been making progress. I think it is about 9Watts average on Atom with newer chipsets, compared to first Atoms which use older chipsets and are consuming 26Watts. That "new" AMD chip for netbooks is an atrocity (IMHO) using about 45Watts.

If you want to run Windows, then you'll want to pass on ARM netbooks.