White still holds the edge though not as big as in the Spanish, the scottish or Italian. Against most variations of the 4 knights black can equalize with a few good moves.
The opening does however have a few mean tricks that even unprepared grandmasters fall for (for example Short vs L'Ami in a Corus some years back). So it is not at all a bad opening against unprepared black players
And for fun to the a3 topic.. in this position a3 is actually a decent move :)
The four knights opening as it infers is an opeing fo both black and white that puts all four knights into the action of the game. Who do you think has the better edge in this opening. If you want show games, main lines, dislikes/likes. This is how it usually goes.