XFX offers a double lifetime warranty, which means it covers you and anyone you transfer the warranty too. Nice little feature that most don't.
Juniper is just a title ATI puts on the 57xx GPUs. They did the whole evergreen theme. 58xx was Cyprus and 56xx was redwood. Don't worry if it's listed in the title or not. Just marketing. http://en.wikipedia.org/wiki/Evergreen_(GPU_family)#Products