The varying angularity and dross levels on the steel part can be caused by:
1. Older technology/design plasma system
2. Damaged nozzle (tip) orifice from drag cutting or piercing too close.
3. Inadequate torch height control.
The stainless cut that you show just indicates that your plasma likely is under-powered for the thickness.
All plasma systems are not created equal......expect better cut quality with better plasma technology. Torch height control for pierce height and real time cut height is critical as well.
Here are some pics from one of my cnc machines with a Hypertherm 45 amp plasma with a good height control system.
1st pic is 3/8" steel, second is 1/4" steel, third is 3/16" stainless, last is 3/16" aluminum