I've been playing in a pair of sprints for several weeks and I LOVE them. They are the favorite shoes I've ever worn, bar none. But then, I've spent as much of my life barefoot as possible, and have strong arches and tough feet. Even so, I've bruised the bottoms of my feet a few times on rocks/roots so far. It really is just a thin bit of vibram rubber on the bottoms of your feet.
If you are considering trying a pair, DO find a place that has them in stock in your size to try on before ordering. I found that it was hard to figure out what size to order, and that the size that fits best in one style may not be the size that fits best in another style... salesman at HTO said he'd had the same experience, that the sizing from one style to the next was a little inconsistent, so definitely try before you buy.
I haven't yet had problems with them wearing out, but I've only had them a few weeks. I've played on concrete and dirt and they've worked well for both. I would be wary of playing thorny courses, since I don't think they would offer enough protection from large thorns -- I think they'd poke right through. But there is plenty of protection from glass, which is my biggest concern on most courses.
I've been looking at FiveFingers for about two years, but held off ordering until REI started stocking them, since I want the REI return policy. I'm not sure how these will hold up -- at least the Sprints. But I know I can take them back and exchange them if need be. If you're going to order, do order through REI.
I wear them for other activities, too, and have found them excellent for all kinds of activity... walking, running, light bouldering, etc...
If you don't have tough feet already, I would recommend the FiveFinger Treks -- more protection on the bottoms of your feet, more durability and a lot more grip. I think they are probably the best disc golf option by far. Ugly as all get out, though. Don't do this for style.
And do be prepared for lots of questions and weird looks anytime you are in public... or even on the disc golf course. If you don't handle it well when strangers come up and ask you questions, don't get these shoes.