The only benefits of FE cards are slimmer size to fit into smaller mini ITX cases, and blower style cooler blowing hot air out of the case, again beneficial for smaller chassis.

The supposed advantage of non-FE with extra pins and big ass fans, is a wash: both FE and AIB cards overclocks close to each other thanks to voltage lockdown. AIB cards may have the advantage in cooling capability and noise levels, but AIB cards dumps hot air back into the case, so you need cases with positive airflow out of the case, and you can program fan curves into FE to match AIB noise levels (noise level is a wash to me as well, unless you game with volume down totally). AIB cards came pre-OCed, but FE cards can match and supersede that with their own overclocks as well.