I am from the UK so this is a view very much from the ''outside'' so to speak.
I would say that domestic has to be better as not only quicker but the ''gear'' has already passed customs checks
The downside is that with the laws as tehy are in the USA there is more chance a USA domestic to be ''popped'' / being watched and not getting your pack or it being controlled.
The International sender may live in a Country where AAS are OTC so no ''heat'' on him sending just when it goes through customs USA end.
Now what i don't know bust sure people can answer is the likelihood of a user getting busted importing a personal amount is greater than the LE wanting to use them as a witness against as USA source?
My general feeling is USA domestic is easier and think if i were in USA that is way i would go but above are two questions i would weigh up
Wrongun!