Originally Posted by spcialzdspksman

SS allows for you to coast, and therefore to rest whenever you feel tired.
FG will force you to always push the gearing, whether you're tired or not.

The intensity level of a FG and SS are the same when both parties are pedaling under the same gear inches, but I assume most people ride SS for the opportunity to coast.

Ultimately, when you compare the total work performed with a SS versus a FG, there is an obvious imbalance, no matter how small. However, as more and more mileage is completed, the actual value of the difference will be much greater, albeit proportion-wise, would be the same.

All this is, however, based on the assumption that other variables are unchanged, like distance, training, gear inches, etc...
In reality, you could have a SS rider with a higher gear inches, or who coasts much less than the average rider, or who trains/rides more, etc. However, these exceptions would be ineffective to compare just the mechanism of FG v SS.