Glad you like this Paul! DE (Distance Estimation) Stop in simple terms allows control of the amount of detail in the rendered fractal. A low DE - 0.08 is the default - gives very fine detail. Whereas 8 - such as used here - results in a much more 'chunky' and smoothed effect. Hope this helps?
Actually Paul, looking at your pieces, you seem to be rendering at a very small size. This will definitely result in a pixellated, low resolution image! Nothing to do with the DE Stop settings. Try using the 'High' render setting?
Are you actually using 'Mandelbulb 3D'? As you refer to 'MandelBULBER' 3D - this is a completely different program with entirely different controls!