Alas, while I have been lucky enough to see Concorde fly, I was never fortunate enough to actually fly IN one. Though when I walked through one at a museum some years ago, I thought that even a 2 hour flight in that cramped, narrow cabin would have been a very uncomfortable experience.

Modern subsonic airliners are now capable of far better speeds and efficiencies. Qantas just commenced one of the (if not THE) longest non stop flights from Perth in Western Aus. to London in 17 hours. I myself flew from Sydney to Houston direct in 15 hours last month. The new generation 787s etc., with their carbon fibre construction enabling them to fly at higher altitudes, combined with efficient, powerful power plants are slicing hours off most long routes.

The last time I flew to London (mid 90's), the Singapore-London leg was 22 hours in a 747. To be able to fly Perth-London in 17 hours is a massive improvement of over 20% reduction in flight time in just a couple of decades.

Personally, I would far rather spend 17 hours in a comfy, wide body aircraft than even 10 in a narrow missile. I do realise that modern SST aircraft may be wider and more comfortable than the Concorde, but there are still physical limits to fuselage cross sections and weights that will limit the comfort factor and size IMO.