I do have several of the Nikon Action EX models, and the 16x50 is clearly the weakest, the image is not really bright and not very sharp either (for me, the 10x50 and 12x50 are the best ones, even better than the 7x35 which is well regarded by many).
You ask for comparisons, and the question is of course whether you mean other 16x binos or e.g. also 12x50 etc.
I can compare it directly with the Nikon Monarch 5 16x56, and the latter is - for my eyes- much sharper, shows better contrast and is also brighter, despite the slightly smaller objective lenses. But the Monarch costs 2.5 - 3 times as much.
Other comparisons might include the Fujinon 16x70, APM 16x70 or similar models, all of which easily outperform the Action EX by some margin, but also cost (much) more. Then you have all the 15x56 models, some of which are very good and very expensive (the cheaper ones I don‘t know myself).
I know people who are quite happy with the Action EX 16x50. For me, it is not a bino I would recommend, Nikon put the 16x optics in the same small body as the 10x50, and this is not ideal (image is kind of dull, not very sharp, and shows more CA than I like). The only big pros that I could think of are compact size and light weight.
My recommendation would be: if the Action EX is within your budget, then buy the 12x50, which is much better and is also much easier hand-holdable. I bet you would see as much detail with it as with the 16x50.
Again, all of this is my personal opinion.