First off, just want to say that Emboar has a beard of fire. Now, read that again and let it dawn on you. A BEARD OF FIRE! 50 points for Emboar.
Anywho, I'm not sure who is better, having never used either one. (I've used Pignite, though)
Emboar has a much more diverse moveset, even though it doesn't learn great fighting stab moves by leveling up. (although with infinite tms, good fighting moves are always available) Sawk, however, has a lot of fighting moves, but it has the better of the two abilities (sturdy, not inner focus ew) and can access different typed moves via tms/move tutoring. Although, I think that Sawk has the better stat spread. Emboar can't seem to decide if it's a mixed attacker or a tank, so it just kind of does both, but not super well. Emboar has great attack and special attack, but is very slow. And along with being slow, it doesn't have the defenses to back it up. AND it has a lot of recoil moves to wittle down it's decent HP. I honestly wish they got rid of the nice special attack and spread it out to between defense, special defense and HP, since Emboar learns a lot of physical moves and just has better attack already.
Sawk, is kind of better at what emboar is trying to be: an attacking machine that can hold its own a bit. With a good speed and decent defenses/HP, Sawk can strike first and take the next hit, which will be a poweful first strike due to its nice attack. And, even if it is OHKO'D - oh wait! It can't! So no matter what, your Sawk will be around for two turns, where it should hopefully be able to hit hard and fast.
So I vote for Sawk, sorry firebeard. :(
*Also, if my analysis seems off, tell me, because I'm just glancing at their stats, and I don't really know much about Competitive Battling XD