Earlier quoted context omitted.
"Please note that some features may not function with certain privacy settings turned off, and some information (such as the association of your Google Account to your OnHub) is stored by Google even if all privacy controls are turned off" I am sticking with my Asus AC66U which has more features and is also cheaper than this Google device http://amzn.com/B008ABOJKS
I'd trust the Google device more simply because Google is better at software. With hardware companies like Asus you get routers full of terrible, insecure software. http://www.securityweek.com/asus-routers-plagued-command-exe... Although I'm sure you're using DD-WRT or something...
http://arstechnica.com/security/2015/08/google-pushes-update...
Here's more... granted, these aren't all vulnerabilities that Google is responsible for, but many are:
http://www.cvedetails.com/vulnerability-list/vendor_id-1224/...