LOOOOOOOOOOOOOL visit the CS:GO forums and it's nothing but negativity. I'm sure it'll be good by launch, but there is so much they've neglected to include that it isn't funny.
Not to mention a key factor of fun in CSS is the mountain of custom maps. It'll take a while for GO to get good maps to play on.
CSS is well worth the money for the best tactical FPS still goin'. Valve did the genre good by creating the best wacky (TF2) and best serious FPS (CS1.6/CSS) so far.
It's already well worth the price, but it usually doesn't go on sale till major holidays, excluding very infrequent weekend sales.