I would go with a color head if you want a diffusor and might eventually do color. Not sure what is common where you are, but all the major brands are at least very good. I have a couple of Omega D5s. Not the best (from comments I've seen), but I can easily get parts and the price was right. I have an Ilford multigrade head on one of my D5s and it is a great setup for black and white. They are also relatively common, but I do worry about service in the future. The Chromega head is very simple and mechanical, so I figure I can always fix it.