I've read The Sparrow countless times, I really love it.
As for the sequel, no, it's not as good. Obviously that was to be expected. If you loved The Sparrow, you might still want to read on about Emilio (and one of the others...), but it'll be kind of rough and poignant. I wouldn't say that I enjoyed it, but I'm happy to have read it, and I've been thinking about reading it again (only read it once so far, a few years ago).
Without giving away any of the plot, the thing I liked about The Sparrow was the huge factor of the unknown. The entire story had this feeling that you just didn't know where it was going -- a sense of uneasiness.
I don't see how you could do that the same way again, at least not in the same universe.
But I've got it on my kindle anyway. Sometimes first books are so good you have to read the second one just to see where the author wants to take the story.