I bought a CZ Upland Ultralight 12 GA 28" for our Denver PF banquet last year, plus a CZ Redhead Deluxe 20 GA. CZ has a great program for helping out non-profit's like Pheasants Forever, DU, etc. Kick-them-Up on this forum is involved with that program at CZ in Kansas City and he has been very helpful for our banquet the last couple of years. We ordered six guns from them this year.
Anyway, those two over-unders both generated a lot of raffle ticket sales. I know the guy who won the Upland Ultralight and he let me shoot it at one of our PF youth training clinics/youth hunts (his son was out there). It shoots fine and would be a dream to carry around all day.
There are a lot of different opinions but in Eastern CO, I walk a LOT and shoot a little. Weight and balance are very important to me. For the last two years I've been using a Lanbar 12GA O/U that I got at Cabela's N.I.B. for $700 that weighs 6 lbs 4 oz on my scale with 26" barrels. I shoot it fine and it balances well, even in one hand while I'm working my E-collar transmitter. Since I don't get very many shots, I don't want to limit myself to certain range shots like I might have to do if I was carrying my 6 lb 7 oz Browning Citori 20 GA. Plus, I've got a 12GA reloader so that also steers me toward a 12 GA.
If you want a lightweight, easy to carry 12 GA O/U for hunting, that doesn't cost you a mortgage, I would highly recommend the CZ Upland Ultralight. If you want to hunt with the gun and shoot a bunch of clay targets, you would probably want a little heavier gun.
Tom