Just received my night sights from a company at nightsighters.com today & put on my SR9. Very happy with these sights. They are low cost & work like a charm. Hope this helps someone looking for night sights that's on a budget like me.
I also have the nitesiters. I purchased them for my LCP but since they included extras I put them on my P89 as well. They are fun and helpful at the range (my poor eyesight) but I would consider them pretty much useless in a night time situation unless the bad guy allows you time to shine a light to activate them. Despite what the website says, I think they dim too quickly to depend on especially when in the dark confines of a concealed/holstered handgun.
They were a great addition though for the LCP since it's sights are so bad that any visual aid is an improvement day or night.