this sci-fi helmet is done with the new Blender 2.8
dynamic topology is at the moment the only way to achive a good detail results, because blender doesn’t manage well high polygons count as Zbrush. But as you can see you can achieve some good results. If you want go further retopology is needed.
here is the lin to my you tube video about sculpting with blender
here you can download Blender is free!