That is not completely true actually. While for the average user things might seem pretty much the same, there are some pretty visible distinctions between the both. As a matter of fact, a very high percentage of developers will tell you that they predominantly use Chrome, both in work and in office.
Chrome is definitely the faster one, hands down. The initial setup is more polished and optimized for better performance than Firefox. That being said FF seem to be much more customizable, providing better functioning plugins which do the job right. So if you know what you are doing you can enhance your Firefox damn well. Same logic applies to security. While both essentially well secured, the FF plugins seem to do a better job of increasing the level of protection you can get from a browser. In terms of syncing Chrome does seem to get the upper hand, making it very easy to sync all information from different types of devices...
...and those are just a few off the top of my head. So I can see where you are all going when you suggest that the browsers are pretty much the same, but for a more advanced user the two cannot be more different (and still better than IE