As said it's either shohin vs Kifu,Chhuhin, mame whatsoever or just penjing vs bonsai.
I read an article written by Robert Steven were he explains:
The main difference between penjing (Chinese: pen = pot; jing = panorama) and bonsai (Japanese: bon = pot; sai = plant), despite the terminology, penjing is more about artistic nuance in portraying natural phenomena; and bonsai is more disciplined in technical skill with the objective of suggesting the physical perfection of an old tree.
Penjing is more symbolic as well as a media for the artist in expressing his emotional ideas.
To a certain extent, bonsai is rather bounded within its convention and rules; where penjing is more free as personal expression.