If you're looking for a some free weights to use, these are a good choice. Lots of advantages here...
-come with a carrying case
-not plastic, made of metal, so one pair is all you'll ever need
Is there anything bad about them? Well, they are heavy (just kidding). Seriously though, I can only think of two disadvantages. Some people might be bothered by the rough handles. If this is the case, a) you will get used to them over time, but you could get callouses, and b) try some plastic wrap on the handles if need be.
Other than that, the only bad thing I can say is that to change the weights, the collars aren't the clip-on kind that make plate changes go quickly- rather they're the screw-on type- which take longer to get on and off, and some might find it a bit cumbersome if you're changing the plates around a lot.
All-in-all a good item to purchase if you're in the market for some dumbbells. And those with shoulder problems might also want to check out Treat Your Own Rotator Cuff
for some good rehab/prevention exercises for the shoulder.