If what you want to do is connect "Things" to the Internet, "B" hits the sweet spot. It's actually a better choice.
For one, if range matters more than capacity or throughput - as it does when connecting to the Internet so as to provide flexibility in the location of the "Thing" relative to the AP - then 802.11b should be your mode. 802.11b has better range and penetration. A 1 Mbps 802.11b signal travels 3 times as far as an 802.11g 6 Mbps signal and 4.5 times as far as the lowest 802.11n data rate. With 802.11b your cost of deploying access points to cover a large cell area is 10 times less than with 802.11g and 20 times less than 802.11n.
Another way to look at it is that due to the increased sensitivity of an 802.11b receiver compared to an 802.11g or n receiver, lower power needs to be transmitted with 802.11b to achieve the same distance. This parameter is critical for battery operated devices as it extends the battery life. This means a battery-operated device will last longer with 802.11b, important since the likelihood is that lot of "Things" will be battery-powered devices.
In addition, 802.11b speed is fast enough for most embedded systems especially when you consider that alternative technologies such as IEEE 802.15.4 or ZigBee are limited to less than 250 kbps. As opposed to laptops or mobile phones, embedded devices use UART or SPI as the host connection, which is generally the limiting factor, not the speed of your Wi-Fi connection.
And GainSpan WiFi minimizes the overall throughput impact of "B" devices operating in 802.11g,n WLAN network. In implementing CTS-to-self to eliminate the overhead of the full RTS/CTS cycle, and short time slots to reduce time between frames, GainSpan increases the overall throughput of a mixed b,g,n network by up to 25%.
When connecting "Things" to the Internet, "B" is better - and GainSpan "B" is the best.