It�s actually really hard to find a router at sensible prices that can achieve 1Gbps throughput which is why we selected this unit after extensive searching.
Even more difficult to find client kit that supports it. Dual-band would provide the best option but I was looking myself a couple of weeks ago and gave up on it. Far too expensive and none of the laptops or phones that get used in my house support 5GHz anyway.
Sadly wifi is pretty much a no-no even with FTTC. Mine struggled to reliably do better than 20Mb/s so I've gone back to a wired connection on my laptop. It very much depends where you live but I'm on the edge of a housing estate and if I remember correctly there are 18 networks visible. I think my WAP managed to get two adjacent channels which is the 72 Mb/s you referred to. But even then you typically only get 40% of throughput from what I've read about wifi.
It'll be interesting to see how it pans out but my feeling was that it ruled wifi out for 'serious' use. It's fine if you're just browsing and reading email but I think you've probably made a wise decision. Wifi is can't provide high throughput and it's probably not worth trying. As long as you advise your users about the limitation I think you've done the right thing