I waffle on this. US to Asia...no coach for me if at all possible. US East coast to Europe...I can deal with coach if the savings is enough. Return flights from Europe in coach are tolerable, since I don't need to sleep. I have booked Business to Europe and coach back many times. Paying an extra $1.5k for business over coach on a 6-9 hour flight is hard for me to rationally justify. One view is that by sitting in coach I am paying myself $200/hour to ride in a chair. Usually I would prefer to have that money in my pocket to pay for a nice hotel or splurge on an outing once I get there. The gist I get from my time on FT is that I am in the minority, but I would much rather fly VS coach on the 815am flight to LHR for 10k points plus $150 than fly business for 47.5K points plus $875. Clearly I can take 4x as many trips.