RE: Over/Under Question
I have a Beretta Silver Pigeon and love it, but it did cost me a nice chunk of cash. Browning makes a great O/U as well. I have to agree with many here that have said either save another $200-300 to get you around the $1250-1350 range in you want to gonew. You can pick up a Beretta 686 Onyx or base model Citori in that range. Used - you should be able to find these and many more quality O/U for around a $1000.
However, the most important point already discussed is fit. Get the right fit. It can a $5000 O/U but if it don't fit right, you won't shoot it well and get really frustrated fast.