Just a quick question…
I am going to be painting my sisters new house…
They just put up the drywall, and are taping right now…
It is a huge house… so I am going to rent a sprayer and spray prime the whole house…
I have been told to use an oil based primer…
Is that necessary? or can I use a latex?
Obviously… I would rather use latex because it will dry faster and would be a bit cleaner…
what is the advantage of oil over latex?
The last sentence in this link explains.
Not much, it penetrates wood better.
BTW, if you use an oil primer you can’t put latex on top of it, well, you can but itll peel off later. Oil stinks so I don’t use it.
I hate OIL anything, Id stick with latex if possible
also, as handy said, if you use latex on top of oil…you look at it and it will peel off 
Latex is really the way to go on drywall; oil is standard only if you’re priming MDF (or most woods). And I’d strongly recommend a power roller, not a sprayer. I have yet to find a sprayer that didn’t run/splotch/generally leave a big old mess. The power rollers are, IME, just as fast and leave a much better coat behind.
-BK