Mud jack or should I use the foam stuff?

I've got a 133 sft front porch that settled about 2-3 inches from when it was built. It's 8 inches thick concrete with flagstone on top. The slab was poured on backfill dirt because the house has a basement with concrete walls. There's also the septic line that runs underneath the porch about 3 feet below. Mud jack quote was $900 and the foam would cost $1500.

What do I go with? Pro cons?