I work for an internet service provider and we are beginning to roll out wireless access points for our customers. I am building wireless network management in to our online customer portal so our customers never need to open the dreaded
192.168.1.1 in their browsers again. We are also giving out multiple APs to some customers with larger homes and our management tools ensure that each AP has the same network settings so wireless clients will correctly switch between APs without losing network connectivity.
We have a pretty awesome solution, I must say. Our router firmwares have an API built in to them so that we can manage them from our provisioning network, and we use this API to push updates and network settings down to the access points.
I have done a lot of research regarding the optimal network settings to give our customers the best wireless experience. The internet seems to be a wasteland of real, concrete knowledge regarding wireless networks. It seems that there are forums full of people waving magic wands over their access points trying to achieve 300Mbps Wireless-N.
TL;DR: The gist of it is that the presence of a Wireless-B device on a G/N network will force the router in to compatibility mode, thus slowing the network connections down for the G and N clients.