Interesting thread. I am an SR9 owner. Probably have about 2000 rnds through the gun, it is a 9mm (I think it also comes in 40)... full disclosure, I also own an Mark II and Mini 30 too. I am big fan of Ruger.
Anyway, I love it. I have a very large hand, I am 6'4" 230lbs, and the Ruger fits very nicely. It's light, well-weighted, and shoots as well and accurately as anything I have tested (though I think Glocks and a number of others mentioned in the thread are great guns too). I hit what I aim at as well as most anyone with training, maybe a little better.
So why did I get the Ruger SR9?
It was a simple decision. Just about all the guns available today come with a trigger safety only. Like the Glock style trigger. They basically assume, if you are pulling the trigger, you want to fire the gun. Generally a safe assumption, but not always. I am not an old guy, but I have been around long enough to know accidents happen. I also have two kids. I am not irresponsible in anyway - but that doesn't matter. They don't call them accidents so you can plan for them.
I'm not a cop or military guy - so I wanted every safety feature that was available. Some might disagree with this philosophy, but if the safety gets in the way of my kid, or some other person who doesn't know what they are doing, actually firing the gun by accident, it is worth the extra risk in a life-threatening situation (at least in my mind). To each his own as they say...
When I asked to see new guns the had a actual button or switch safety in 9mm or .40, they had about five guns in one of the largest stores in NC. When it got cut down to that, the $405 SR9 was an easy decision. I am very happy with the gun.
Every gun is a selection unique to the user... but please keep the safety of yourself and your loved ones in mind when you select and get the right weapon. Probably .00001% of any gun's lifetime is spent shooting... it is important to think about the other 99.9999% as well.
My only complaint, is that it is not full metal frame. I own Smith and Wesson revolvers my great grandfather purchased around the turn of the century. They still work fine, I wonder of all these plastic guns (mine included) will be around as long.