Is it Safe to enter Google Password in 3rd party apps?
If you're worried about it, my suggestion would be to use Google's 2-step verification on your account. Basically, when you're signing in to your Google account from an untrusted computer (one you haven't successfully signed in with before) then in addition to your password you will also need to provide a 6-digit code that can be generated by an iPhone app or texted to your phone. That way, even if your password is compromised, no one can log into your account without your phone.

For apps like RSS readers, Google also lets you set up randomly-generated one time use passwords to sign into those apps that you can revoke at any time.