So I tried both the Boker, and the Giesen this morning. Neither one was what I would consider to be in a shave ready state. I know they can both be way sharper than they are.
I don't straight shave full time at the moment, but when I do use a straight, I am finding that my Kai Captain is far easier to deal with: the blade is either too dull to shave with, perfect to shave with, or slightly too sharp.
I think at this point I have reached my limits on how much money I can invest into straights, and may sell off everything except for the Kai Captain.