I used a femidom once in a punt. As you penetrate you get that screeching sound of the bag, which can be annoying. However my cock stayed rock hard throughout the punt, which was a great help as I did anal throughout (staying hard is way more important than the baggy sounds).
From that experience I would say femidoms are far better than condoms (which are erection killers).
It's such a shame that ladies do not use femidoms enough.