If you could pick between going to a Gracie Barra gym or a Fabio Santos gym which would it be. I am thinking of going and visiting family in Cali and was thinking about trying one of these out.
It all depends on who the teacher is.
Unless Fabio's lineage is going to pop by and teach you, who the teacher is at each gym should probably be key in your decision making.
If you are thinking of stopping by Fabio Santos school in San Diego (the one where Fabio Santos teaches), then I would definitely recommend dropping by there. I went for an open mat 3 years ago and couldn't have rolled with a more friendly and skillful group of guys. Very welcoming and cool and the Black belts were kind enough to train with me (I was a purple at the time).
I second jrv's post. I trained there for a month about 5 years ago as a bluebelt. I think fondly of my training there.
Lineage alone should be at the bottom of your list, unless your only concern is bragging rights 
I am pretty sure Fabio still teaches every class at his school so...
mjm345 - Lineage alone should be at the bottom of your list, unless your only concern is bragging rights
This^^^^
I am from the Carlson Gracie lineage and MJM345 is not, but I would bet if you saw us roll with people without any patches on you would think he is Carlson Gracie way before me.
my lineage would kick your lineages ass
Alizio - my lineage would kick your lineages ass
My lineage has a Mustang with a supercharger
First of all lineage does not matter to me in the least. My experience is more with submission grappling and MMA than just purely BJJ. One of the gyms I am choosing between is a strict Gracie Barra school, and of course I went and visited. The other school is a taught by a Fabio Santos BB, but it is a Relson Gracie affiliate. Since I know that there are differences in the approach of each school in regards to their teaching styles I figured people on here would know have opinions. I could careless about bragging about lineage, but the teaching methods do matter. Does this clear that little matter up?
if your going to fabio and paying, im sure you could go train with alex and work on your spider guard if you wanted .i thought fabio was a rickson or rolls bb