Google WiFi provides free wireless Internet for the city of Mountain View. It is a great free service. Here's the link that convinced me to use Google WiFi as my only source for Internet. He's got an interesting setup with a directional antenna. Having said that, Google WiFi has been inconsistent. Sometimes I get 1-5 KB/s, which is slower than dial-up modem. Usually I get 10-50 KB/s download and upload speeds, which makes web surfing more manageable.

A good forum for Google WiFi support is here. This forum post helps measure your signal to noise ratio so that you can find the strongest signal in your home. To find the best spot, I literally walked the entire house with a laptop running Netstumbler, a software tool that shows the signal strengths to the various wireless access points surrounding your home. You can also add this plugin to your Google homepage to measure your signal strength to the nearest Google WiFi node. There's only one spot where I can get decent signal using the Pepwave Surf 200AP, a recommended modem for receiving Google WiFi indoors. It cost about $77 ($65+shipping) from eBay, so the experience semi-worth it considering Google WiFi is free and DSL or cable modem is about $20/month.

A number of users in the Google WiFi support forum have decent reception, around 30 SNR (signal-to-noise ratio) and -60 dBm, but don't get good bandwidth. See these posts: post 1 and post 2. Additionally, there is rather significant data loss as measured using ping. To ensure that you get consistently good bandwidth, I think you need a 35 or above for SNR and less than -60 dBm. This is bare minimum. Otherwise, the signal will be noisy and bandwidth can fluctuate, often falling below 5 KB/s.