If, as Les says, there is a full grade difference between cold cathode and condenser enlargers. (I've never used a cold light head). It isn't surprising that a photographer going from one to the other would be initially disappointed with the results from his negatives. After all, we all do those boring film tests to tune our negs to our own methods and equipment. I have a feeling that once someone adapts his whole process to the characteristics of the light source of his enlarger, the difference in results will be fairly subtle.
That would initially seem to be the case. However my results don't indicate that to be true. What I have observed is that the light in a well designed condensor system is collimated (aligned along an axis) and that does bring certain conditions to bear in the print. The first is that as Les indicated grain becomes more apparent and that negative defects become more noticeable. The reason for this is because the light being collimated moves through the negative density in very perpendicular fashion. This condition also brings some pretty nice characteristics as well. Those being that print sharpness is markedly improved. The local contrast is also enhanced. Since local contrast is acknowledged as being the characteristic that causes the glow in a print, I find this a enjoyable addition to my process.
I don't readily accept most of the theory and conjecture of those who may not have tried all aspects of a process. That would include testing the paper used for exposure and development charactersistics and following through to the light source and ultimately the camera negative characteristics.This is the only manner that would appear to offer the means from which to draw valid conclusions. I indicated that I don't readily accept conjecture today...this is one of those areas.
Les mentioned that the manner in which light is scattered in a condensor light system... That would more accurately be stated that it is in the diffusion light source that light is scattered. That is the reason for the smooth gradation, less noticeable grain, and negative defects that were mentioned. Those characteristics occur because a diffusion light source tends to smear the demarcations of local contrast and density border regions due to the scattering of light in that source.
Obviously if one has not tested and developed their negatives to the light source and the paper that is being used then a valid conclusion is impossible to obtain. Conjecture remains just conjecture.
I have no axe to grind in this matter other then what I find to be true in my considerable experience of over twenty years using all types of enlarger light sources with the exception of a point light source. I don't agree that the same result is obtainable with the two light sources if the negative is tailored to the light source. That would only be true if the quality and condition of the light being presented to the negative was the same.
Having said that, I recognize that everyone should use what they find to deliver the result that they want.