Hey, CON-PILOT I honestly hope you are talking about London (Canada) not UK
No, I meant London, England. The 900EX/EASY can make that leg non-stop when the temperature is low enough, which it is most of the time in the winter, especially early in the morning. I've done it. (To be honest I've forgotten the actual temperature, it's been a while since I've thought about it.)
As for the 900EX/EASY cruising at FL450, it not a big deal. Admittedly one cannot go straight to 450 just after a maxi mun gross weight takeoff, however, you certainly can after cruising for a few hours at lower flight levels.
Same with the 50EX.
As someone already posted, you cannot compare the G-V or the Global Express to the 900EX/EASY. The G-IVSP, or whatever it is called now and the 900EX/EASY, yes.
Now as for DOC hourly cost between the G-IVSP and the 900EX/EASY, the 900 is lower due to the lower fuel burn on the 900, however, the difference is not that much. If I recall correctly it would take about ten years to see a real savings. One other minor point is that the 900 has lower airport usage fees because it is lighter than the G-IV/whatever.
As I previously posted, both aircraft are great and I would have been happy flying either one.