I also have a decent?! collection of amenity kits around different airlines, but most of them are from UA C cabin. Just flew in from NRT on NH. NH gave out very nice bag to put in an assorted amenity items from a basket. This bag from NH is by far the best of all amenity kits received (aside from the content) as I can use it for travel kit (put decent sized shampoo, lotion, etc.). NH had a very nice set of pajamas, but I wasn't allowed to take them...
As for content, SQ is one of the best... especially with their Bulgari perfume.
As for UA kits, I use one of the newer ones for camera cover (DSLR). Other ones are unopened and remain in the boxes in my storage.
By the way, I actually make a good use of newer UA F amenity kit. I use it as a travel document wallet.