I went for leica noctovid after looking through the NL pures..
I found the leica are a tad heavier but the picture they give seems more 'real' , I also tested them against the zeiss sf.
You would definitely be getting an optical upgrade from el to NL although I still think the el takes some beating in the handling, especially as the NL has a larger and more protruding focus wheel (i sold my zeiss ht bins ages ago as the larger wheel meant more fiddling to focus after removal from a bino harness).
Best to go try some and see for yourself if you think the expense is worth it.