Well its hard to say, because any advantage or disadvantage humans have (same for any race) is measured realitively to all the other races.
My views on humans are known on this form, and its probobly best if I don't start that debate again, but I'll ignore them to be more constructive to this thread.
Personally I like the way Animorphs played humans, one of our main advantages was population (common to most earth life actually), there is a quote that sums it up: (from memory)
Alien underling "Population 6 Billion"
Alien leader "Surely you mean 6 million?!"
(We were also a super fast race for developing technology, but the aliens had a head start)
I found makeing human the highest quantity race to to be a nice little subversion for against the stories that made humans the highest quality race
Other advantages humans have could be based on how human empires behaved: Militaristic and economical. We' probably get a disadvantage to "real work" since as soon as we become rich, we push all that stuff to cheep foreign labour. I'd also like to give humans a scientific penalty, just because of all those times humans have a massive scientific bonus, to the point where "human ingenuity" reaches the levels of a deus ex machinia. X-com did that for example.
Graphically humans should go out of their way to look as advanced as possible with extra flash weapons (and take a small penalty for wasting effort on this). Humans nearly always have the same mostly inelignet designs, so just to be contrary we should avoid this. Besides we actually used to do this, look at old fashioned military uniforms that only went out of fashion when guns made camouflage a necessity.
Note, a while back I proposed the possibility of a racal special based around how human empires behave, so naturally its a perfect fit for humans, read it here