I use it, on and off. (month on, few weeks off... I get yeast issues if I stay on too long.) But, it does seem to help. It's not a miracle drug for me, but it's helpful.
I could never stick to Flagyl long enough to know if it helped (ICK) but Cipro was close to Xifaxan, but harder to take. Besides, Cipro has that tendon thing, which I felt just enough to scare me away from any sort of long-term use.
--40 year old female, dx as UC in '04 (1st symptoms in '03), switched to Crohn's in '05, 1 fistula, crohn's colitis, limited to large intestine
--rejected (reaction/didn't work): Asacol, AZA, 6-MP, MTX, Remicade, Humira, prednisone
--methylpred - finally off 6/15/08, tried Prochymal in Phase III study (can't wait til it's approved!)
--started Tysabri 3/21/08
--single mom to 10-yr-old girl