Foam jacking as alternative to piers?

[Philip Hy]

I have a rental property in DFW area that is having foundation settling issues (no surprise considering the region). One side is down 3 inches. Ramjack quote me $10,000+ for 12 piers ($830 a pier)! Ramjack seems like an industry leader, but plenty of companies quoting $300 a pier. Am I getting something less with the cheaper companies? Has anyone tried expandable foam jacking? Seems like a very attractive alternative and a fraction of the price. Desperately need advice, please don't fail me dear Forum! Recommendations for companies are welcome!