A while ago I compared Astronomik CLS with their UHC-E and an Orion UltraBlock, in a filter wheel in an 8" f/6 Newt in suburban Sydney... Performance depends very much on the object of course, so I don't think there was a clear winner.
But if I were to have only one out of those 3 (under less than black skies) it would be the UHC-E - just a bit more punch than the CLS, and not as aggressive as the UltraBlock... closest to 'jack-of-all-trades' in this environment, if there is such a thing.
I have never looked through the DGM-NPB though, but I have never heard any negative feedback about it...
just my $0.02
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