Dear Stealth: Burn rates and evap rates DO matter, its not just the heat produced but, how fast the fuel will burn completely.
There are hundreds of articles on this by a plethora of Manufacturers and racing programs.
We are in the age of some pretty exotic fuels as the additives get more and more complex.
We did dyno testing on our known 512 /10.75 /trick flow heads engine to find out what fuel it liked and, yes, race fuel is certainly most consistent, but the engine made best power at 93-95 octane.
100 octane lost 15 hp, no timing adjustments or carb adjustments would bring that back.
110 race fuel lost almost 25 hp.
89 OCTANE was down as well, even with pulling a little timing, but down less than the 110..
When we talked to VP RACING FUELS we were told that the 93/95 octane fuels do, indeed, have a faster burn rate than the higher octane "simple fuels" .
If we were to go to oxygenated or more exotic ( very expensive ) fuels we could pick up a little power as they do, indeed, have faster burn rates .
We were looking for ways to offset the really bad air quality we have in Texas these days and that is only going to get worse as our humidity levels are going to continue to increase year over year- Da values will only increase.
Its normal in summer here to be at a track 500 ft above sea level but Da at 3500-4000 ft thus, we are constantly looking for ways to offset that, the water molecules displacing oxygen in the air.
Of course Vp recommends a fast burn oxygenated fuel thats correct for the compression ratio/cam profile etc.

Still a bit reluctant on those fuel because of the extra maintenance program required and Dom hasn't put out much info yet on working with these fuels.
All that to say, ( sorry for the long post) every time i talk to Vp racing fuels, burn speed is something they bring up .
Its not nearly as critical in 6500 rpm engines as it is in 10-12 k rpm engines but, is indeed, part of current fuel technologies as far as im told, literature we receive.

Hope this is of some small help.