The 3G version gives you internet practically anywhere with a monthly allowance of 100MB for free for 2 years via Verizon's network. The WiFi version only allows you to connect to WiFi routers or hotspots which means you can only connect at certain locations while on the go or at your home. If your smartphone supports it, you can turn it into a mobile hotspot which will allow you to be on the internet while on the go, but this might incur additional charges based on who is your carrier.
Dear Mr. Knott, I recently purchased the 3G version of the Chromebook. The difference is that the base unit has WiFi only, allowing you to connect to any wireless computer network, that you have access to, such as your home, office, hotel, airport etc... The 3G is very handy since it allows you to connect to the Web through the telephone system. Amazon also provided 100 mb of data transfer through Verizon per month for 2 years. In summary with the 3G you also get WiFi which means you can connect almost 100% of the time. Hope that helps. Ralph Kettling. firstname.lastname@example.org
The only difference is that the 3G version comes with 2 years of free access to the interent via 3G so that you can access the interent even when there is no WIFI available. Note however there is a 100MB per month limit on free 3G access. I bought the 3G becuase I had lost my interent service due to a storm for 10 days and with this I would have had access to my mail, news and banks. I will be ready for next time.