This doesn't seem terribly surprising. Both Facebook and Apple are very polarizing companies. They have huge fans and also huge detractors.

Google seems generally "useful" to everyone. They don't tend to have the same polarizing effect Facebook and Apple have.

And, of course, Twitter is just too unused by the general public.

Even the reasoning behind people's perceptions seems relatively easy to gauge:

Facebook's core product deals with personal and sensitive information that causes privacy concerns and seems to make the service more "personal".

Apple seems elitist to some. Probably because of their historically high priced items.

Google's core product is simply giving you access to information on the web that isn't particularly personal and provides a lot of real world value to people.