I have an SD9 and I love it. It is light weight, very ergonomic. I can use all the controls(mag release and slide lock)without altering the position of my hand. It holds a lot of ammo 16+1. It has a front night site from the factory. I have put several brands of ammo through mine without any problems. Take down is very easy, just like a Glock. The only complaint I have heard from people is that the trigger is heavier than a Glock. I had a little trouble at first hitting low left but with practice and getting used to the trigger I have worked that out.
If you ever have a problem, Smith has a lifetime warranty. If you want to know anything else PM me. I will gladly help you out as much as I can.
I have a SD40 and also love it. The trigger is heavier than my M&P40C but it's not terrible. I maybe have 200 rounds through it and no malfunctions at all. I've been told the trigger will really clean it's self up and get a little bit lighter after it's good and broken in.
I like my buddies SD9, shoots real nice! I'm not a fan of th eway the trigger breaks but it's a nice pistol for sure. If I shot it more the trigger probably wouldn't bother me the way it does.