One of the considerations should be the location of the sun during the day or evening when you think you will be sitting there. Unless you plan to have a roof or vine over the swing (arbor?), then you may have bright, hot sun hitting you in the face as you sit and swing.

Maybe you could ask over at the Landscape Design forum?

Did you decide where to put it?
I like it in front of the magnolia. then it could see all over the yard and still talk to people on the porch.
Just my thoughts.....

I would hang it within the porch area. That way you get lots of shade and have solid structure for attachment.

I have a yard swing. Mine's a kind of "swingset" design so I can move it around. This is what I've found from my experience. The ultimate garden swing experience is placing it where it will not have the sun shining in your eyes at any time when you are sitting there, shading it from the hot midday sun, and placing it where you have something beautiful to look at most of the time when you are sitting in the swing. I have the additional issue of trying to prevent the sucker from getting blown over in my wind tunnel yard, but if yours is attached to an arbor you won't have that problem. Oh, and you don't want to have to mow around the base if you can help it. It's just a pain, that's the only reason for that advice.

I have noticed on really hot days that in spots slightly higher than others it feels a bit cooler, maybe because of air movement.

Being able to talk with others, the view, and shading are also, as already mentioned, major considerations. Privacy for self and neighbors can be another.