NS are a really personal choice.
Even just looking at them it's hard to tell what you favor.
Try to borrow or rent some guns with various sights if you can.
Things have come a long way from traditional green three dot.
Not that those aren't still great sights.
And the kind of shooting you intend doing has something to do with that selection as well.
Close Quarters Combat sights for fast target acquisition
in all kinds of light?
XS Systems 24/7 Express Big Dots are hard to beat.
For combination short and long range with more precision?
Trijicon HD, Ameriglo I-Dot Pro, TruGlo TFO, Heinie Straight Eight
and more are all worth a look.
Multi color and vertical vs horizontal - things have changed.
Have fun and good luck!