The maduro FDO's do get much sweeter after at least 6 months.But,I think they are sweet from the door,just not as sweet as aged.
The corojo is my other favorite FDO and also does great with age,it smooths out the spiceyness of the raw new bundle.The corojo I had yesterday was 9months old under 65%RH and it was so damn tastey,smooth,and burned perfectly.
The burns on FDO's are a perfect even burn and bright white strong ash that always goes 4in or better,especially the maduro.
I will take an FDO over a roly,connie,or el credito any day.