My OnX is quiet. I can hear it in a quiet room, when I'm bending over from sitting to tie my shoes, when I stretch before running, lean into a mirror, or stand in front of windows or doors. When I was at Cardiac Rehab, the tech could hear my valve while I was talking with her, we were standing a few feet apart, but I could not hear it. I cannot hear it right now while I'm replying to you. I hear it at night(quiet room) but it does not bother me, it does not keep me awake.
Overall, I'm very happy with my OnX, I'm waiting to see what the clinical trials tell us as far as reduced INR, not necessarily reduced coumadin dosage. I'm on 40 MG a week now, no problems, I test at home, call in my INRs. The amount of coumadin needed to keep you in range depends on how your body metabolizes it. Some folks take 5 mg a day, some take more. Coumadin has not interfered with my activities and what I want to do.
Everyone is different, reaction to meds is different, what is right for each of us is different. Read as much as you can on the ACT forum, home testing forum, valve choice forum. Lots of good information here and lucky for us that VR exists to provide 'real life' experiences.