A waterless wash requires no rinsing vs. the bucket & sponge approach.
UWW+ has Polycharger in it which gives the product some additional "boost" for the LSP and for enhancing gloss/shine. ONR does not have Polycharger but has it's proprietary formula that also provides some "boost".
How Polycharger Works
While to a degree that are somewhat interchangeable, in a strict sense UWW+ is a Waterless Wash and ONR is a Rinseless Wash. I have both and use them as follows:
ONR --> Clay, QD, Rinseless Wash
UWW+ --> Waterless Wash, Rinseless Wash & QD
I also have
Pinnacle Waterless Wash w/ Carnauba that I tried last year via a trade. I like it a lot. At some point I will center on either Pinnacle or UWW+. ONR will remain in my arsenal. And realistically by the time I need to make that decision these products may wind up with new and improved versions and the evaluation could theoretically start all over again.