Hi Mike!
We use both expessions the same way, but not to start an enumeration as I've read above, but to start a formal speech.
"Primero que nada me gustaría agradecerles (a ustedes) el haberme invitado"
We olso use those expressions to say what we have to do compulsorily before other things: (but that doesn't mean you're going to enumerate them)
"Tenemos que entrar en el túnel, pero primero que todo hemos de ponernos los cascos"
Actually, here in Spain even more "antes que nada" or "antes de nada" and also "primero que nada", but "primero que todo" is not as used as the other expressions (despite of the fact that seems to be the more logical)
We often use double negatives:
"No me gusta nada" (I don't like it at all)
We (here in Spain) ever say "me gusta nada" but maybe is used in another countries.
"No lo he hecho nunca"
(I've never done it before)
"Ella no me da nunca la razón"
(She never says I'm right)
But is easier to say "Elka nunca me da la razón" in this case.
I hope it helps :)