Guncollector, I do not think that you had any bad luck. Lets look at the knives and do the math.
The Sebenza is a thin stock knife (compared to the 1/4" Busses) and has a thin/fine grind and edge. The Busses have a final edge that is not as thin as the Sebenza; they have more steel behuind and alongside the edge. The Corvette is a great car, but not my first choice for pulling stumps of towing heavy trailers.
In as much as I have and use all of the involved knives I can tell you that the Sebenza shines for slicing and lush cutting. The Busses, while sharp, will certainly endure more abuse (work) without degredation of capability. This is not because the Sebenza is a bad or [iweak[/i] knife, but because its execution of design was for different purposes.
Read through the Wilderness & Survival old posts and you will see many threads about "What's you favorite slicer and chopper?" This is because experienced outdoorsman know that different functions require different tools. I will typically bring a Busse (usually the Natural Outlaw) and and slicing folder with me on outings. The Busse sees all the tough work and supports functions for which a hatchet or small axe would have been used. The slicing folder see more of the food prep which typically involves push cutting and slicing of media where binding against the geometry of the blade would cause more effort and apparent reduced capability.
Look, it's been often said, and I agree, that the Busse can do it all, but a Corvette and a 4X4 pick-up are two different things, each excelling at their intended functions with caparatively poorer performance once outside their respective mission profiles.
I said all of that to say this: I do not think you got any bad luck or dull Busses at all. Do your limbing, chopping, digging and prying with the Busse and leave the pepperoni for the Sebenza.