If they dont come with them, I usuall replace the factory plastic with either factory Glock or Meprolight three dot night sights.
The factory plastic sights work OK, but Im just used to both the three dots and night sights that its what I prefer on anything I can get them on.
I too wish there were better offerings in the width of the front sight and gap of the rear. Both the plastic and any of the night sights Ive tried, all have about the same width front sight/gaps, and it can be hard to get a quick, precision sight alignment.
One advantage to the three dots is, they offer their own sight picture and that does make things easier. Ive been using the dots for so long now (since before they were even lit), I actually see the dots before I see a traditional sight picture, and only start to look to that, once I get past 20 yards or so.
Just as an experiment, I did recently try a set of Ameriglo's plain black sights, with a thinner front sight, and a larger gap in the rear. It gave a sight picture very much like my Browning HP, and a few other older guns I have. They worked well, and when deliberately trying to shoot groups, I found that I was shooting tighter groups and I do believe thats because I was getting a better sight picture.
I also quickly reinforced why I prefer the night sights too, as, even in daylight, I would often lose the front sight/sight picture on targets that were dark, or had a dark background. This only got worse too, and the light diminished. Night sights arent just for "lack of light", they give a good aiming reference in all light.
If youre looking to change your plastic sights out, and want night sights, Ive heard from a number of sources now, that Glock will replace what you have with their factory night sights for around $55, which is a real good deal if true. Just send the slide in. Im assuming you pay shipping at least one way. I plan on doing so here the next time I update mine, as thats about $25 cheaper than what I can get the sights alone for off the web.