https://www.youtube.com/results?search\_query=maya+vray
https://www.youtube.com/results?search\_query=3ds+max+vray
or just look for plastic material. in max you have so many tuts.
why is that so?
Because there are a lot more users of 3ds Max and V-Ray for 3ds Max than there are users of Maya.
Best regards,
Vlado
Yes, must be it. But why? I thought maya surpassed 3ds max in almost any field?
Does vray 3.1 maya has less skills than 3.3 3ds max?
At your website, it says: Render most scenes up to 20-50% faster with V-Ray 3.3 for 3ds Max! V-Ray 3.3 for 3ds Max introduces new variance-based adaptive sampling for quick setup
That does not agree with the maya 3.1 list. 
Does CHAOSGROUP prefer max more than maya at vray?
Should i change because of the amout of tutorials to 3ds max?
Cheers. 
Official versions of V-Ray for Maya really come after 3ds Max, but when they come, they have generally fewer issues (since they are cleared by the 3ds Max users :)). Maya is really about the scene graph and flexible shading/animation networks, better scripting, Linux/OSX support. If you don’t care about these (like most people outside the VFX), 3ds Max seems to be the most common choice.
Both of these will be available in the next V-Ray for Maya update too. The speed differences in Maya can be even more drastic.
Does CHAOSGROUP prefer max more than maya at vray?Nope, we have no preferences really.
Should i change because of the amout of tutorials to 3ds max?This is up to you really; V-Ray works the same more or less everywhere. The large part of tutorials for V-Ray for 3ds Max are applicable to Maya as well.
Best regards,
Vlado