Would say that pussy feels better for me. It's self-lubricated and can feel velvet like and smooth. And a woman can be penetrated for hours--which is what I prefer to take my time.
Whereas, with a guy...it's a different energy. It's definitely more aggressive and intense in it's own way. The angles for me, while topping, can be awkward with height and size coming into play. But it's definitely a bonding feeling.
Ironically, getting topped by a dude is much more nicer than both choices haha. But I tend to really get emotionally connected when I've bottomed; so I don't do that unless I'm in a relationship with the guy...which makes my experiences more of topping experiences.
I would say that another thing that I like about sleeping with women is that you can pick them up (presuming they're petite 115lbs and under); penetrate them while kissing them. Kissing while having sex is very intense for me.
There's one thing that I would not be comfortable with is being fucked by a chick. If I'm getting topped, it has to be the real deal! haha. Although this hasn't happened and don't anticipate it happening, but this reminds me of my fantasy of being in a MMF 3-way--me being in the middle of it all
That's my take