If he had sold both of these to me without even mentioning that there was a problem I would not have complained anyway. The ergonomics of the TUSK are excellent as well and are described in its initial review linked to above. The TUSK has the thinnest point out of all three knives but there is no real question of weakness. This advantage however may mean the TUSK tip is more likely to break off on a full powered strike into very hard materials such as encountered during digging or survival type situations. I did not test this but will be glad to if some wants to send me one.
All knives take a razor sharp edge and therefore slice relatively well overall.
The khukuris are hampered by their excessive forward balance which makes slicing with them fairly tiring as you have to fight the downward pull of the blade. The Sirupati has a more neutral balance than the Ang Khola which makes it easier to work with, however this advantage is somewhat reduced by its extra length. The TUSK is much more neutral in balance the the khukuris and there are no comfort or fatigue problems in slicing with it. As for performance. The khukuris slice better than the TUSK on these soft materials as the serrations on the TUSK often just catch and pull the material towards you rather than cut it.