I can tell you, I have bred collareds for a few years and have had great success with using 2-3 regular incandescent lights on top (75-100 watt), and one or two small 18" fluorescent lights in the tank with an zoomed iguanlight 5.0 UVB. I've never had any lizards get MBD to my knowledge.
I also hear of people breeding lizards, and never using UVB lights at all...who knows. The people selling those lights definately want us to know the benefits though. :P Hope that helped out a bit,