I usually do certificates from Discount Tire. I'm kind of expecting to burn through at least my first pair fast, so I don't know if it's worth it.
For rim protection, it's kind of like an extended warranty. It's more of a convenience, you curb your wheel, take it into the dealership where they have contracted with someone local to do them. From my experience, it probably won't be the best repair around. If you were to do a little research, you could probably find someone to do a better job and just pay as you damage them. I guess if you curb wheels a lot it would be good to have unlimited repairs.