You can try 3D coat or mudbox. Both pretty simple. With 3d coat, you don't even have to worry about retopology. This gives you a lot of freedom. Mudbox is pretty simple if you started out in maya, because I think most tools that it use is embedded in the sculpting section in maya 2016, and it's controls' default are already set to be alike that of maya. Furthermore, they link very easily. This can act like a bridge to learn zbrush.