The nitro seal for me was a little more work than I cared for to apply. I found it to be a bit of a bear to buff down any high spots. Now there's others here that have used it and found it to be quite simple, so maybe take my experience worth a grain of salt. I will say it did look great, was very durable, kept our vehicles cleaner between washes, and made washing/drying easy. If you can get the application process down, its a damn fine product.
I can't quite give you a ton of info on the black label yet as I haven't had it on that long to mess with it. Application was definitely easier (wipe on, wipe off....along the lines of opti-seal if you've used that before) and it looks good. We are just getting out of winter, so I haven't washed it much yet to really evaluate and obviously I can't comment on durability since its only been on a few months. A bottle will do several vehicles