Ok, so this is just my personal opinion. I was obsessed with them for a wile because I REALLY wanted to try it. I ended up trying one at an adult club and it wasn't "all that" Its worth something to try but don't overly expect anything. XOXO, SK

There is a lot of different swings and price points. The comfort of some of them is simply not there. Some are certainly more comfortable than others. Access and positioning also varies from one to another. The bar up top can be an issue as well. They can be a lot of fun with the right swing and right people allowing for positions not possible without it.
Pollie  

If you want to fuck for a long, long time, without wearing out your knees, etc., a sling is truly an amazing thing to have around.  Sometimes I play with men who want me to bone them for hours and hours.  It's so much easier and more fun with the swing.  Plus, as a top, you have total control over the body of the person you're penetrating in terms of rhythm, etc.  The swing allows you to move the other person on and off your dick instead of (or in addition to) having to use your hips to do the thrusting.  It can take some time to get used to the motion, but once you've got the "swing" of things it's a really wonderful addition.  You have to get a good quality swing, of course.  As many have mentioned, not all are created equal, and many of them are uncomfortable.

I don't have one in my Incall in NYC currently, but I'm wanting to get one... because I love them!!  

I have one hanging in my bedroom and all the asian girls know what it is!

freaks

its also very comfortable for sitting in and watching tv.
When my back went out it was the only place I could sit

with lifting your partner up while standing?  Is the experience similar or better?

Thanks all for the feedback. Sounds like something worth a try if it's there, but probably not worth making an extra effort unless I've discovered a personal affinity.