I thought one couldn't tell the difference between 802.1 n, g, or b because all 3 are far faster than the bandwidth of your cable modem or FIOS.
In other words, the internet to your house is the limiting factor on speed, not the router type.
802.11n should "fly" no faster than any other, no?
Unless there's a lot of other traffic on your wifi network, this is mostly true.
My Internet access speeds at home peak higher than can be handled by 802.11b alone (FiOS 100/50), but g and n should handle it well.
Internal traffic is something else, however. Two wifi Apple TVs and three 802.11n-capable laptops and their various traffic - surfing, syncing, streaming, Time Machine hourly backups, etc., are on my n-only network. And now two iPads added to that. My 3rd Apple TV is hardwired.
Three older b/g-only laptops, a Mac mini, 5 iPhones, two iPod touches, an X-Box 360, a Blu-Ray player, two TiVos, a Wii and two Airport Express speaker sets are running off my b/g network.
But, given the nature of what and when the devices are doing, my b/g network probably has more spare bandwidth than the n-only network.