I can't really comment on the iPad idea but in the context of Lenovo's malware install...

If you're purchasing a computer with Google software on it aren't you already handing everything to Google?

So is a Chromebook really an alternative if you're rejecting Lenovo tablets for poor security/privacy?

I've been interested in Chromebook hardware but have rejected them for security reasons previously. I'd be interested to hear other people's opinions on the mater.