Kabar makes a good knife and I think most people like their nighthawk's but the SOG has gotten some poor reviews, namely this one http://www.cutleryscience.com/reviews/seal_2000.html by Cliff Stamp. I would suggest that in a relativley dry environment the kabar takes the cake but in a wet one the nighthawk would be superior. Although of the two I have found Kabar's design to be more geared to fighting than to general use. My biggest dislikes of this design is that nasty full guard and weak pommel.
P.S. You might consider taking a look at the BK&T line of Camillus http://www.camillusknives.com/1mainframe.htm?bkt/index.shtml~main (spectacular knives IMO)