I agree with you Chuck, it does give your position away, but having been in an area where a shotgun was chambered, I have seen it quiet a full room in a hurry and send chills up my spine. I know that if the bad guy is not ready to deal with a shotgun coming at him, he will tend to flee and though you do not have a dead bad guy to prove anything, you still saved the day and accomplished your goal of self defense.
No disrespect meant on my part, just a statement of fact as I know it. I have both an 870 and a Mossberg 500. I have used both extensively and for hunting I prefer my Mossberg 500. The reason is, my first duck hunt I dropped it in the water and had to dig it out of the mud that was three feet under water. After filling my waders with water and getting my shotgun out of the water, I rinsed it off in the lake, ejected the rounds and dried it off on my shirt put three rounds in it and shot a duck all in about five minutes from dropping it to using it.
So I am just a bit loyal to it. My 870 has been reliable and so has my winchester (forget the model #). I only have one semi-auto and it is a Beneli. Love it though. I do tend to use my Mossberg most of the time, it was cheap and just works all the time.
You should get a pump gun for reliability and ease of use issues. Then you should practice, practice, practice with it. You need to know that weapon in your sleep. In the middle of the night, you need to use instinct and know where and how to operate your weapon. Oh, and I personally like the idea of scaring away the threat instead of sneaking up on him and shooting him. I really don't want to have to do the paperwork and the cleaning behind a dead guy in my living room trying to steal my flat screen TV.
Just my .02...
Mel