I assume you're printing with a condenser at present. I tend to agree with Carl's note that essentially you will get a very similar diffuse pattern of light with a Dichroic head as with a Cold Light. Like with all things photographic there is going to be alot of opinions on gear. I personally havent found any advantage to using a Cold Light over what I use (Magnifax Dichroic). I've used pretty much every type of light source that there is and I've found that I can make very similar results with any of them with a little futzing around. The spotting thing can be an issue with condensers although it wasnt a huge one for me, but that issue can be easily rectified with 3-4mm thick translucent milk-plexi...its what I did for years...it also helps with neg popping...and it only cost me ten bucks. Anywho something to think about. Good luck with your choice.
Larry D. Horricks
Prague, Czech Republic