A friend of mine just purchased a low-end Weatherby semi-auto 20 Ga. shotgun. This was her first firearm purchase, and she new NOTHING about guns, so I volunteered to teach her.
Last October, I purchased the Beretta 3901 from Fine Firearms. Here's what I learned from both of these experiences.
I purchased the Beretta for a trip to Canada. I literally picked it up on Friday night, then jumped in a truck and headed for Canada the next afternoon. I didn't bring another gun. BIG mistake! The gun needed a couple hundred rounds through it before I could count on it to cycle reliably. So I was pretty frustrated when I tried to take a follow-up shot on birds, but the 2nd and 3rd rounds required me to slap the action closed because it only closed halfway. The gun shoots great now, but it does need that break-in period. The second thing that happened was that the front sight bead fell off, never to be found. Not a big deal, since I don't use it anyway, but worth mentioning. Finally, there is a roll pin in the action that tends to fall out (according to the good guys at Fine Firearms). On mine, it worked itself halfway out, but apparently, if it had fallen completely out, I would have been up a creek. The good thing is that Fine Firearms replaced the bead, and swaged the roll pin so that it will be less likely to come out, free of charge. Thanks, guys!
Now on to the Weatherby. I told the lady that she might need to put a couple hundred rounds through it if it was anything like my Beretta, and sure enough, it had feed problems. We noticed that it especially didn't like the Winchester shells she had purchased for it, while the Federal WalMart cheapies I had purchased worked much better. Now that we've put a couple hundred through it, I believe it's working much more reliably. I don't think we had any jams on our last shooting trip.
In summary, my thoughts are:
1. Both guns need a good breaking in.
2. Both guns seem to work well after the break-in.
3. If you choose the Beretta, watch out for loose sight beads, and especially, loose roll pins in the action.