They share a 30mm arbour/bore size on the blade, but the Bosch is a 254mm blade diameter according to the specifications, so the 260mm Kapex blade may well cut into the bed of the Bosch even if it operates OK without binding anywhere.
A lot depends upon how much you are going to use it and what you are going to use it on. Any reasonable blade that is new will cut pretty well. What mostly differentiates the highest cost blades from the lower cost ones - not the lowest cost garbage blades - is the quality and quantity of carbide on the blade. The better carbide dulls slower and more carbide will allow the blade to be sharpened more times.