I have the Pro version of these lights and have difussers on them. I really like how they evened everything out. Great blending. Lost very little Par with them.
The blue for me, I had the xr30 Gen 5, had a lot of disco effect. The diffuser ended that and smoothed everything out.
The only part I don't like about them is that they hold heat in a bit. Never thought that was a good idea personally, but it didn't seem to affect anything.