I've never owned a Red Dot sight and really don't know if it would be worthwhile to mount on the gen 4 G17 that I use as my primary home defense gun. I have a Streamlight mounted on the rail and assume I would buy one that clamps onto the top of the frame. Does this add much in terms of quick aiming in low light situations such as I would likely be dealing with in my home? The stock sights seem pretty clear to me in the daytime, but maybe not so much at night. The distances that the gun would be likely used in my home is likely no more than about 15 to 20 feet. And if you are recommending adding a Red Dot, I would welcome recommendations for modest priced sights. Thanks.
In my not so professional opinion, much like for rifles, dots are pretty much the future of handguns. Even with that profound piece of useless info, I think that most folks don't need dots and would be FAR better served with taking that $$ and getting some or some more training.
I made the transition cause the old mark 1 eyeballs were just not cutting it with changing focal planes and I was essentially shooting target focus with irons. I could still make do, but I just figured if I'm going to be target focused, I may as well have a sighting system designed to function as such. So do you need a dot or do you want a dot?
If you already have a non-MOS G17 the cost of a dot will be either an aftermarket slide or milling factory slide PLUS the cost of the optic. Not cheap. While some of the adapter plates are OK, IMO they place the dot way too high above and you will be fighting the transition a bit more. Not impossible to overcome, but why go that route if you dont have to. In this respect the closest you're going to get to a dot being on the same plane as irons is an MOS Glock with a Holosun SCS.
No matter what you decide, understand that the transition will take work. The irons offer a cheat that the dot does not. While you may not notice it or even think about it, your peripheral vision does in fact see the irons much earlier in the presentation of the gun and as such you start making presentation tweaks. With the dot there is nothing there till you are on the last portion of the press out and getting on target. If your presentation sucks cause you've spent 30 years cheating, so to speak, you will need to relearn things. And that process will be frustrating, especially if you are half decent with irons. For me this was frustrating at the onset of using the dot. I was VERY glad that I made the transition while I could still use irons and did so on defensive guns till I was confident/competent with the dot.
With respect to the modest pricing, I think you're going to be hard pressed to beat Holosun for a decent balance of reputation and pricing. Trijicon is pretty expensive these days.