It depends on what you want to do with the gun! Hunt or target shoot. I've been trap, and skeet shooting for 4 years now. I just recently purchased a Beretta 686 White Onyx over under " sporting" shotgun. It fit me great and actually inmproved my shooting because it fit me. The down fall...... I cost me $1600.00!! And because it's a sporting gun it looks really nice, so I do not hunt with it. I hunt with a Reminton 870, and it works just fine! Before duck season I usually hit the skeet field with the pump instead of the o/u to get used to the fit. I guess I don't feel as bad if i get mud and water on a $380.00 gun compared to a $1600.00 gun. you are right semi's are dirty (I have a Beretta 391) but they do the same thing a O/U will do! O/U can have just as much go wrong with them also, acually if somthing does go wrong with it it's more expensive to fix because they have to completly take the gun apart.
Hear are some things to keep in mind:
1. What is the majority of the guns use for?
2. What is my budget?
3. What (if any) kind of hunting am I going to do with it?
4. if you get only one gun and plan on hunting and sport shooting with it, make shure the chokes are rated for steel shoot!!! You can put lead through a steel choke but you can't go the other way around. you can damage your choke and barrel!!
Here are the guns I have:
Remington 870(pump)=duck hunting gun
Beretta 686 White Onyx Over under= trap,skeet, and clays gun
Beretta 391 semiautomatic trap grade= back up incase the O/U breaks down. (yea i shoot A LOT )
Just some things to think about from one shooter to another and I hope this helps!