Their website is sketchy at best, but they call this a "full-pressure, single gas (O2) suit." That sounds like a low-pressure pure oxygen suit to me, which would cause decompression problems unless, like U-2 pilots and others, they flush the nitrogen out of the passengers before flight. That raises a few other safety issues, but at least it's a proven technique, and could work.

I don't know what XCor's cabin pressure spec is. For these suits to work effectively it would need to be low-pressure pure oxygen.

I do know that Rutan's vehicles are Earth atmosphere at full pressure, and that he tends to fly shirtsleeve. I'm not that comfortable with that idea.

Not sure exactly how this all works for the Shuttle's Advanced Crew Escape Suit.