Hm.
Usually I like to discuss differences between XIOM and other brands but this is toughy.
But I hope my honesty can reach you.
Okay,
here it goes.
Sigma II and Vega Japan are 3rd generation rubbers from XIOM.
The basic structure of Vega Japan is quite similar to Sigma II Euro.
Please note Sigma II pro and Sigma II euro are really different.
Sponge is different and even the hardness of the sponge is different.
If you want to compare Vega Japan with Sigma II.
You must compare it with Sigma II "Euro"
So, the biggest difference?
Sweet spot. Vega Japan has larger sweet spot compared to Sigma II Euro.
While Sigma II Euro is made for higher catapult compared Vega Japan, and it is harder to play with.
While Vega Japan, to be frank is really really top noch rubber with almost everything from Sigma II, but easier to play with.
Also it is cheaper.
Honestly Price for Value, I recommend Vega Japan.
Once you are comfortable with Vega Japan, then please move to Sigma II Euro.
Thickness available.
1.8
2.0
Max (2.2)
chow