To me, the sensation is different because its in the way. Not in MY way, but in YOUR way.  Apart from that, I admit I feel less at ease with a FC in place due to its appearance- because a properly placed FC must remain partially external, what was once a pretty pussy (yes, I like mine; it's an "innie") is now a pretty pussy with what looks like a freezer bag hanging out of it.  The sensation of DATY is really not different, your full access to it is. I hope that makes sense to you. As far as sex with a FC, my opinion has always been that for me it is no different, and I simply offer it for the benefit of my partner.  I'm guessing if I were a man I would dislike wearing a condom a great deal. For the guys that hate condoms, they are fantastic. However, back to aesthetics- I have heard numerous times that the appearance of the FC is a deal-breaker for men...especially those who LOVE to DATY.  These guys would rather wear a traditional condom than see their female partner's parts somewhat concealed by the FC. In the right situation, the FC is fantastic IMO. Apart from a party for a M/F, any party with a M and more than one F demands these! I cannot imagine breaking momentum because a condom had to be swapped out; buzzkill!!

You asked for opinions, I hope this is helpful.  

Peace,

Astrid