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Just looking at my spreadsheet which I keep track of on maintenance. Back in June 17 2010 (146615 km), my car had a tranny fluid change (it was just a drain and refill i believed). I have it noted down that the next tranny fluid change would be 194615 kms or on June 17 2012.

What's the concensus regarding the cheaper drain and refill versus a full flush?

 
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A drain and refill is the ONLY method Honda suggest.

A flush would multiple drain and refills.

 
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Flushing with chemicals and a machine is "strongly discouraged".

 
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drain and fill only

 
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Multiple drain and fills will allow you to remove most of the old fluid. But keep in mind the law of diminishing returns...I think a drain and fill replaces 1/3 of the fluid.

Just as an example here are some iterations of drain and fill. Assuming capacity is 9 quarts. 3 quarts replaced every drain and fill (not sure if these numbers are accurate, YMMV) Assuming after each drain and fill the car is started and driven for a period of time thus a homogeneous mix of the transmission fluid is achieved.

1st D&F - 3 quarts new, 6 quarts old (easy as pie)
2nd D&F - 5 quarts new, 4 quarts old (removed 1 new quart and 2 old quarts, added 3 new quarts)
3rd D&F - 6.33 quarts new, 2.67 quarts old (removed 1.66 new quarts and 1.33 old quarts, added 3 new quarts)

I would stop here as it only gets worse in that you are removing more and more good fluid and less and less old fluid.

4th D&F - 7.22 quarts new, 1.78 quarts old (removed 2.11 new quarts and 0.89 old quarts, added 3 new quarts) ***You are beyond wasting money here***

 
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i did 4 drain and fills when switching to different brand and it got most of the old stuff out. capacity is only 6 qts i believe so by the 4th drain and fill, you should only have less than 1/2 quart of old fluid left. you really only need to do that many drain/fills the first time. after that just do a single drain and fill each year to keep the fluid fresh.

 
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Yeah, if you are drain-and-fill once a year.... one time should be enough.

Because I'm a dorky engineer, I busted out excel...and you are right. But notice, if you do just two, you have 75% new inventory.