I don't have a whole lot of experience with Busse and kin, having only handled a few and owned only a couple, so anything I say can be taken with a wee bit of salt.
Personally, I feel that it's a bit of an "apples & oranges" comparison. There are some Busse designs that don't make a whole lot of sense to me from a practicality mindset but in the end, if it makes someone happy, who am I to judge? On the flip side of that, there are Busse designs that I adore and I keep a casual lookout for them - I'm never in the right place at the right time though so it usually ends up being a fruitless exercise in patience.
At our Beckerhead Gatherings (twice a year before Covid happened), Busse is often the butt of a joke I haven't figured out yet. Those who have been to a BH gathering know that attendees aren't gentle on knives and due to the Busse's reputation, if one is present, it gets the honors of enduring some of the most ridiculous and grueling hijinks. That said, you know what has NEVER happened? A Busse doesn't break and it just shrugs off any and all abuse. It is a testament to the steel quality and its legendary toughness - knowing this, I would never hesitate to own one.
CPK is a different animal. I love the thought and care that goes into absolutely every detail in the design and making of a knife. From the steel to the handle design, the purpose built philosophy, and the exacting standards, CPK really is a cut above so many (no pun intended). If Nathan can take a design as seemingly mundane as a Kephart, reproduce it somewhat faithfully, and still manage to imbue it with his own special stash of unicorn blood magic, there is surely something to be said for that.
If I may, I'll use the following analogy: Where CPK is like a finely tuned AR-15, with precision and careful thought built into every element, including the ammunition - Busse is like an AK-47, you can beat the living crap out it and it will still spit out bullets with the best of them.
In the end, they aren't the same, you're comparing different design philosophies and manufacturing methods. They both offer amazing knives though and that is really what matters.