I guess depends on the result you're after,each has pros and cons.
Start from posing can have unique details,like foldings that follow the pose,muscle that react according to movement etc,get really dynamic result.
But then all parts will have unique uv,unique topology and only works in that particular pose.
Posing in the end is more organize,can utilize symmetry and reuse parts to keep the model optimize,but the result could be less convincing since the details/flow are done in T pose/A pose.
Huge pros though it is a complete character,can be animate or pose in different poses .
If action figure,sculpture or there is a certain pose you want for the character,then pose first should be ideal.
Plus there's no limit on textures and polycound for this contest,and you're using substance : )
