Carry a gun, carry a flashlight too. It's dark about half of every 24 hour period after all. And lots of places inside can be dark even in the daytime. Train with both and you'll do about as well as you'll be able to do no matter what happens.
My current carry gun (S&W 642) doesn't have night sights, though my previous one (Glock 19) did. Those snubbies which do have night sights usually have just one tritium lamp inserted in the front sight, or have a replacement front sight installed that has a lamp in place.
But my snub does have a set of CT Lasergrips (the Glock didn't).
If you train to use sights you'll use them by default, assuming you can manage to get the gun up to eye level so you can actually see the sights. Sometimes getting the gun to eye level isn't a possibility though. The laser works from any position, eye level or not, which is why I have one on the S&W. A short class from Southnarc and another from Clyde Caceres late in 2005 at Andy Stanford's Snubby Summit made me a believer in CT.
Defensive long guns (shotguns and carbines) here all have night sights as well as white lights, but none so far have lasers.
As far as time to line up sights is concerned, you'll have the amount of time you have. The closer the target the less time you have, up to the point where you don't really have time to even draw a gun at all. That's where ECQC (
http://www.shivworks.com/pdf/ECQC Course overview .pdf ) or the equivalent comes into play.
http://www.downrange.tv/blog/drtv-weekly-myths-and-techniques-on-self-defense/11957/ or
http://blog.hsoi.com/2011/10/19/youve-got-a-hammer-but-everything-isnt-a-nail/
Keep in mind - there are no hardware solutions to software problems. What you're talking about are mostly software problems, though some aspects of hardware can help sometimes - when they work, of course. Gotta remember, Murphy loves you and if you depend on a crutch, that will be the first thing to fail in a pinch. Train and study, study and train... Murphy has less luck with software, if it's installed properly.
Stay Safe,
lpl