I used an Aristo on my old D2 for many years. I now use a diffuse light source on my Saunders. However after reading the material on the Durst USA site, I would strongly consider buying one of their condensor light enlargers if I were wanting to purchase the system that is best capable of producing fine enlarged prints.
I had never thought about it when I started that the thing that is nice about diffuse light sources is also a detriment as well. Diffuse light sources (cold cathode and dichroic) simply are incapable of producing as sharp an image as a well designed condensor light source. You will notice that I qualified that as "well designed". Not all condensor systems are equal.
I obviously have "no axe to grind" in this matter. This is my opinion based upon the results that I have seen.