I know it's not the greatest marketing pitch, but it's the truth.
Google is bent on establishing platform domination unlike anything we've ever seen, even from late-1990s Microsoft. Google controls Android, which is winning; Chrome, which is winning; and key Web properties in Search, Youtube, Gmail and Docs, which are all winning. The potential for lock-in is vast and they're already exploiting it, for example by restricting certain Google Docs features (e.g. offline support) to Chrome users, and by writing contracts with Android OEMs forcing them to make Chrome the default browser. Other bad things are happening that I can't even talk about. Individual people and groups want to do the right thing but the corporation routes around them. (E.g. PNaCl and Chromecast avoided Blink's Web standards commitments by declaring themselves not part of Blink.) If Google achieves a state where the Internet is really only accessible through Chrome (or Android apps), that situation will be very difficult to escape from, and it will give Google more power than any company has ever had.
Microsoft and Apple will try to stop Google but even if they were to succeed, their goal is only to replace one victor with another.
So if you want an Internet --- which means, in many ways, a world --- that isn't controlled by Google, you must stop using Chrome now and encourage others to do the same. If you don't, and Google wins, then in years to come you'll wish you had a choice and have only yourself to blame for spurning it now.
Of course, Firefox is the best alternative :-). We have a good browser, and lots of dedicated and brilliant people improving it. Unlike Apple and Microsoft, Mozilla is totally committed to the standards-based Web platform as a long-term strategy against lock-in. And one thing I can say for certain is that of all the contenders, Mozilla is least likely to establish world domination :-).