Not being a big semi-auto fan but involved in shotgun sports a long time. My take is any semi-auto that has been around for awhile, has decent CS, shoots 3" shells and is adaptable to a sight would be good to go. The most important thing is a good fit.
As far as sights, red dots leave me cold, a good low power variable with an illuminated dot will do every thing a red dot will do and have better optics. I do like Holographic sights and have one on my bow and my 870 set up for coyote hunting..
I have 1-4x20 Leupolds of all series on my combo guns.
