That's very interesting indeed. Its probably a case of "it depends who you talk to" at Sky CS. As nine times out of ten they won't help.
But as said if you're on a super budget then go TP Link, if you're mid range look at Asus, if you want the best go DrayTek.
I only have experience of a 2710n, but it's nowhere near the best.
The advertised QOS simply doesn't work at all, sync is lower than the Sky supplied box, and the UI hides options in stupid places.
I'd consider doing what I've done, and stringing a gigabit Tomato router off the back of the Sky one and simply using it as a modem

-Leezer-