I use a sling. It's kind of uncomfortable on my bony shoulders (I constantly switch it back and forth), but it's not too bad in cold weather when you're wearing heavy clothing.

If you're going to walk around with it, DO NOT use one of those Primos slings with the snaps and all. I made the mistake of laying the bow next to me while glassing, only to have a mountain goat pop up in front of me. I looked down and noticed to my horror that my bow was all buttoned up. I needed 15 seconds (and too much commotion) to unsnapped the whole shebang; unfortunately, billy only gave me 14.