I own both and I will say MY blacks are more laid back than my fawn.
That said, I have to say my friend's black is just as wild as her fawn and they both are related to my Shushu thru a granddam. Shushu is my most laid back.She was always my lap baby.
Also I think because pugs are wild/busy hard headed, pups and I mean until 2 or 3 yrs old, then they are sofa lumps. So they get a reputation for wildness from their complete stubborn puppyness and joyful attitude towards life.
Pugs have a really strong stubborn streak and you must work with that to train them.
And the younger the better. The way people treat their dogs like human spoiled baby is absolutely the wrong way to train a pug, if you want to have a well behaved one.
The breed isn't for the namby pamby IMO you must be the dominant one from day
Truthfully I haven't really gotten as attached to my fawn bitch, Mei, she just is too willful for me lol
And the SHEDDING, UGH! she sheds way more than my 3 blacks do.