Do 180g vinyls sound better or is it a myth ?

Also, the plural of vinyl is vinyl.

+1 mofimadness!

And besides, they are not 180g vinyls as the title of post says.  They are 180g records!

 Does the weight of the vinyl make a difference to overall sound quality,

Absolutely not.  My best sounding records are not 180's.

and to add a bit more substance to the post, does it sound better than CD

Vinyl sounds different.  Not better.  In most case, I prefer the differences that vinyl offers though.