Sans, I think Saudi fits in with the oil sheikhs I mentioned earlier.
Taiwan? South K? Maybe. Japan? Maybe. Have they flown the fatigue life out of their 53E variants? But I suppose they can indeed afford a V-22.
As to why on the difference in noise, 53K is heavy lift, and has more payload than V-22. (It also hasn't yet had a spectacular crash near DC during a development flight ...)
It covers a different part of the mission mix.
K is less risk, tech wise.
K is less controversial in its development timeline.
Note: the GAO report from last year and program move to the right is a concern. Cost is still a concern. GAO report seemed to indicate to me that program has mostly sorted out such problems.
Given that large helicopter tech is pretty mature, there isn't as much need to hype this aircraft, so it makes sense there isn't as much blather about it as Osprey. Nearly thirty years to IOC (Osprey) isn't an impressive timeline, is it?
That's what can happen when one takes risk with bleeding edge or new tech.