Hi Phang !
sorry for the late reply !
I don´t think there is much difference in quality between the two - It`s more a difference in the finish and the target market and the concept of the companies .
The Hazet sockets have a combined matt/polished finish/look with a very helpfull double knurling which sticks out while the Wille sockets have a knurling which is inboard (like the snapon sockets) and a matte finish with turned "heads" but no polished appearance like the Hazets.
Hazet
Stahlwille
So the Hazet concept is to have a matt (sandblasted on wrenches ) finish always combined with a polished part (except open end wrenches and bit sockets)
Stahlwille has this smooth satin like finish on their wrenches , extensions, ratchets etc. and a matt finish on their sockets
I own almost everything from Hazet since they`re easier to get + i like the design better and the matt side and knurling makes sense, you have a good grip if you turn the sockets with your hand , yet they`re easy to clean on their polished heads e.g. so fitment on countersunk bolts is no issue. So you have both advantages of easy cleaning which is better with sleek polished/chrome plated tools and a good grip because of the matt rough side and the double knurling which is better if you have oily hands or rust remover is all over the place. The wille sockets offer less grip but they are a fraction thinner .
But since it`s not bad to own a tool twice I`m currently building another socket/wrench set with stahlwille tools so I don`t have to decide.
