I just started working on NRT and after going through the product i liked nice one unlike PureDisk and NetBackup . I can say NRT would be mixture of PureDisk , SF + VCS and DeDuplication addition to the snapshot inteligence. NRT lacks on the high config especially limited to certain models , not sure why Symantec had to so keen on this selected models.
I also found its both phase procedure of installation was almost similar to what we experienced in PD. (except for NRT doesn't allows customised partitioning , which i disliked the most)
As seen NBU appliance 5200 can we expect NRT appliance (might be bundled with stated models)