Interesting observation. I have just upgraded to the HH5 and was getting 58Mbs over ethernet. Tried a dual-band Netgear dongle and am getting 63 Mbs on 5GHz. So Ethernet is not always faster. (The line checker says that I should expect about 62 Mbs over ethernet). The 5GHz speed drops off though if I go into the next room, but not by much.
Moral of the story..... in the same room as the HH5, 5GHz wireless might be faster than Ethernet.
Dell Studio1558 with Win7 Home Premium
HP Pavilion netbook Win8 8GB RAM
IE11 and Live Mail
BT Infinity 2 via HH5
(Virgin 150Mbs as backup)