On a long flight CO no question but you are looking at 6.5 hours flying time. If you are very lucky and eat no dinner or breakfast you might get 5.5 hours sleep. Eat any meal and you are down to 4.5 hours. Can you put up without a perfect seat for 4.5 hours? The A330 PHL-MAN flight is miserable but its mainly because of the service as much as anything. The seats are bearable for the time you have (far better than the 767s out of LGW) and it will be a late flight so its not that difficult to fall asleep. I think PHL is a much nicer place to spend time between flights than EWR. If it were me, I'd rough it on US Airways. I'd soak up as much Yuengling as the PHL Envoy Lounge bar staff will give you, aim for 4.5 hours after a bite to eat and a movie, skip breakfast to maximise your sleep (because they wake you up too early) and save your £250 for another trip.