Toughness can be a touchy subject with many dealers / makers and you often get hit with "its a knife - not a prybar". That being said :
Ontario can make a very strong knife - however there have been wild ranges in performance in the 6 similar blades that I have used and only one that I would actually call acceptable. 4 of the others all showed flaws in materials or heat-treat and the remaining one had a non-functional design. Ontario does not have a strong warrenty.
The Uluchet is a small hatchet that is very durable. I pushed it very hard and I did nothing except shear off the stop pin in the handle (which does little to effect functionality). The warrenty on the Uluchet is very strong and P.J.'s didn't mind anything that I did. The ironic thing about this is that the Uluchet is a folding "knife" and it has no trouble going against large fixed blades.
The A1 is also a very strong knife. I have not done any heavy prying or direct edge strain testing yet but it looks to be very strong. I should have a review finished in a week or two. I don't know what the warrenty policy on this is, but unless it surprises me, I don't think it needs one.
I have other blades on the way that might be of interest. The first being the well known Trailmaster from CS (which might get here by the time I get my BM it seems), and the second a heavy khukuri from GH.
For future projects I am looking at a Busse's blades, and a couple of custom made 10-12" blades in Talonite and 3V. The latter being the supposed heavy hitters. 3V in particular interests me becuase its very high charpy value means that I could have an very thin profile and still retain high strength. I also have a MPF ordered from Mission (4-6 months), and would probably be interested in the larger Ti version MPK.
-Cliff
[This message has been edited by Cliff Stamp (edited 18 May 1999).]
