I haven't used one myself, but in my time messing around I've never seen anyone complain about the FatMan products. They seem to be a quality engineered, well built product line used by a bunch of people.
If you're looking at going IFS & IRS have you considered picking up a salvage Jag XJ6 and using both ends? Might be an option to consider to get OEM parts and save some bucks, too.