This is one of those areas that can turn into a can of ..... something. My take on this, having used both condenser and diffusion is closer to what Les said above. It is the printer, not the enlarger.
The same discussion might occur between unrelated endeavors, such as guitar players..some would prefer a Strat, others a Gibson, still others a custom job. In the end a great guitar player will make any quality guitar sound great.. just as I would expect Les to be able to make a great print with just about any quality enlarger. He adapts his technique to the equipment, but the final print will sing because of the master printer..not the enlarger.
This is so much like the debates over Nikon vs Canon; Beseler vs Durst bs Omgea, it is not the equipment, but how well we learn to master what we use. Some folks just think in terms of cold light heads, others condenser and still others diffuse light ..I have a Beseler/Minolta 45A that makes no sense at all to me, but many prefer it.
Just my rambling and that's all...