I am glad that my thread has sparked a lively discussion and debate. Further contributions would be greatly appreciated as well.

Just to clarify a few things from the comments above:

1. Since I live in YOW, it is 2 transit points anyway: with CX it would be YOW-YYZ-HKG-BKK and with NH, it would be YOW-ORD-NRT-BKK. However, it is much faster and easier to go with CX since I avoid the American customs thing, as well as the unpredictable nature of short flight cancellations into and out of Chicago during bad weather.

2. I do not take AC because I had too many bad experiences with their service in J. I used to be a SuperElite and after feeling badly treated, I switched. I am much happier now.

3. I am primarily interestd in flying between Canada and Asia, on a carrier with top notch service (therefore preferably an Asian carrier), and if possible in F. Therefore, the AA programme would give me free CX flights, but I can't use any of their upgrade features.

4. From what you all describe, a central 'power' feature of being a diamond is that you get on flights whenever you want seats, even last minute. This is indeed an excellent feature suited to last minute business travellers, particuarly premium passengers who need to jet across for an important closing... I am not one of those customers. I do fly a lot (150-200K per year) but almost all of it is planned at least a month in advance, and often 2 months. I seldom change the date last minute and my local professional commitments do not permit too many changes. Therefore, this feature of the diamond membership is not useful to me.

So unless there are other features I don't know about (quite possible), the benefit of CX to me would be shorter transit times and avoidance of US customs, and the benefit of NH would be much more generous upgrades.

For me this is a really tough call. The transpac F experience on Asian carriers is really nice, even if you have done it many times before. However, as we all know, long flights with transits can be exhausting, no matter how you do it and so shorter times can make a big difference.

I still don't know...

FF