This probably will not help but FSA will be releasing a ‘K-Force’ carbon crank sometime after May that will be something like 45-grams lighter than the Superlight!
Now for your question, we (wife and I) have both DA and FSA Team Issue cranks and unless you decide to up the budget and splurge on FSA Superlights or the K-Force cranks when they are available, then the only differences you have already pointed our are weight, stiffness (slight difference in both weight and stiffness according to a test Tom D. did last year), and the coolness factor of having FSA carbon cranks. In the long run it is your bank account and trust me when I say it does no good to buy one over the other if the one you settle on will not make you happy over the long run - which is probably why we will be getting some FSA Superlights next month.
Michael