I personally prefer a semi-auto for both uses. I have trouble short-stroking a pump under the stress of competition and assume I would do likewise during a hostile encounter at home. I do shoot mine quite a bit in competition and have found it to be completely reliable which is an absolute MUST for defensive use.
Mine is a Benelli M1 Super 90. It happens to be pre-ban but it wouldn't matter if it was post since I prefer the standard stock over the pistol grip style anyway. I have a CQB Solutions Tac-sling with an integral buttstock shell carrier. For competition I also have a forearm (human forearm) carrier and a series of kydex clip on belt carriers (2 shells each) which tilt out slightly at the top. I like the 2-shot models because I can add or subtract as many as I need at that time.
I also prefer the rifle type sights (actually look more like pistol sights - square notch and post) over the ghost rings. I find the open sights to be faster although a little less accurate at longer ranges. So far accuracy has not been an issue.
Mike