I liked this. It was probably cheap to make and it wasn't that exciting, or had many special effects, but I'm finally begining to like Vala as a character and for the first time the power of the Ori was evident and they suddenly became a much greater threat.
Vala's past was bound to catch up with her eventually, but one wonders if she has any friends at all out there. The life of an ex-Goa'uld host must be pretty lonely.
The 'matrix-style' stopping bullets, the plague, and the general superior attitude of the Prior was quite worrying. The Goa'uld or the Wraith can't do that. The Prior could have easily killed SG-1, but his motives for not doing that are clear. They can now not help but spread word of the power of the Ori, and that is exactly what the Ori want.
I'm with Daniel though, when he wondered exactly why the Ori want every human to worship them. What can such all-powerful beings gain from it. I'm sure we will find out.
So, they are father and daughter, and they don't get along, because he left them due to the air force, for some reason I thought the explanation of their behaviour would be more interesting.