I upgraded to the 7270 after my 7170 decided to fry and die. On first use, the 7270 clearly has a much stronger WLAN signal than it's predecessor. It's just as easy to set up and the wireless signal uses the N standard, so speed is much quicker.
One feature that I really like is you can set up an additional "guest" WLAN network for when friends, family or business customers come to your premises. This saves the hassle of changing passwords and allows you to set up a simple, temporary wireless network without compromising security.
I am presently using two SIP VOIP phone numbers based in the UK and USA on this box and both lines are crystal clear, with minimal delay. A great all round box that is worth the higher price tag!