Nag nag nag
If you do choose another search engine as default, you will likely be frequently pestered to change back to Google. Whenever I use any Google service a dialog appears offering to install the Chrome spyware^h^h^h^h^h^h^hbrowser. There is a 'No thanks' option, but what is lacking is a 'Never' or 'Try me again in 5 years time' option.