I used them for the first time recently to try them out. They did exceptionally well, as they stopped the enemy for a while and did a reasonable amount of damage, while my other units could regroup and get ready for charge. They are very cheap and even if they flee early in the game it is no big loss.
I'd always keep the general near them though, cause of their crap LD6.

I've never heard of Fiesa Gitzas..But they seem like Sneaky Gitz..Did you get them out of a Spanish article?

No, in the German army list they are called Fiesa Gitza.
Probably the same as Sneaky Gits - goblins with 2 hand weapons and poison attacks and some special rules.

Yeah, they're Sneaky Gits... I don't play CD, too slow but, I think they'd definitely have their uses. They'd wreak havoc against lightly armored opponents. The poison would let them take on big things like ogres a minotaurs too. I'd use them if they had high toughess low AS. They're cheap too

I also like the fact that they can never be surrounded, but instead can always surround themself, even if they lose the combat round. The general should be near though for the break test.