I would disagree with El Cid about Ontario being on par with Ka-Bar and Camillus. A search on the forums likely would reveal that Ontario has quality control problems (uneven grind lines, and similar problems.) Camillus and Ka-Bar are much more consistent in QC.
I would take a Camillus Marine/Combat over the Ontario one any day.
Other things you have to think about are heat treat. I have no experience in comparing Ontario/Ka-Bar/Camillus. However, it is my suspicion (take this with a grain of salt) that Camillus' heat treat on their Marine/Combat knvies is better. Keep in mind that I am talking about the Spec Plus versus the Marine/Combat knife that Ka-Bar and Camillus make.
What Ontario does offer, as said, is great value. If you need a knife to dig, poke, hack, chop and th elike, and you only have $40, the Spec Plus line is great! Also, Ontario offers unique things like the Bagwell bowies, and the new collab stuff with Jeff Randall. Ka-Bar and Camillus offer way different stuff too. You can only compare parts of these companies, really. Camillus makes tons of knvies for other folks, they make high end production stuff (CQB-1 and CQB-2, Talonite blades, etc.), traditional slip joints, high tech modern folders, etc. They use "cheap" steel and they use TALONITE!!! Ka-Bar is using D-2 and offering more higher end stuff too.
I see Ontario as being the good cheap guys. Their Jeff Randall collab stuff can be thought of as an attempt to compete with the good mid range stuff offered by Camillus and Ka-Bar. I think the Ontario RTAK is going to sell FAST! But for inexpensive stuff, I'd rather go with a Camillus C/U 7. but that i sjust me. If Ontario floats your boat, GREAT!