I remember the first time I didn't use one when she gave me the green light to go in ...... "are you sure??" A nanosecond later I was balls deep and it was just incredible. I was surprised I lasted as long as I did. Condoms were so thick then, it was like wearing an inner tube.
Honesty if I didn't know he had a condom on, I'm not sure I'd notice vaginally. But if I know upfront, it makes a big difference mentally. Just not as exciting or thrilling or messy with a condom.
I'm a vagina bearer, and personally, I HATE the feeling of a condom. Condoms here tend to dry out pretty quick (almost like they just absorb moisture or something), and once they do, they feel like fucking a plastic grocery bag. Not to mention, mentally, while the idea of children terrifies me to my core, the idea of being, for lack of a more subtle term, "filled", is quite a turn on. Only done it raw once, but damn, I wish I didn't have to go back As for the dick wielder's experience, it seems to depend on the person. My previous partner (though we never had intercourse) said it felt exactly they same, while my current partner also greatly feels a difference like I do, both mentally and physically. (Granted, we both have Sensory Processing Disorder so certain sensations are much more heightened for us both) Regardless of all these, we still use condoms, to protect ourselves from potential infections, or pregnancy, because even couples who both are clear of STDs and STIs are completely monogamous, have a very minor risk of contracting one anyway.
I use condoms with the majority of my partners. Putting a few drops of lube inside before rolling it on my cock makes a huge difference. If that is done I cannot tell the difference. I only go bare if there is no threat of passing infections along. But even bare we usually use lube. That I think is the key either way. If you use lube and, like someone else suggested, use the correct size you may not be able to tell the difference. I can't.