you said 'clays' - and then mentioned "skeet" ......so I'm a little concerned that we are not communicating yet on what you want to do ....
In general, on O/U's - for general shooting ( which to me means bird hunting, sporting clays and skeet ) - I like a gun around 8 1/2 lbs, and 30" barrels. I find the weight is about right for a lot of barrel movement left and right.
For Trap, I go to longer barrels ( 32" ) and a gun around 10 lbs ... / and I shoot the same gun for singles, doubles and continental.
Picking a gun is all about "Fit" - meaning it hits where you look. Its probably fair to say, at this point you don't really know what the stock dimensions are that you need ( drop at comb, drop at heel, length of pull, etc ) .... Until you really know what fits you ( and different gun mfg's are different ) don't buy a gun / spend some time at a club - talk to a lot of shooters, try a lot of guns and see how this develops for you.
I'm not saying you can't shoot a pump or semi-auto / because you can. But in terms of 100,000 shell durability, reliability, etc the medium priced O/U's are solid guns ( primarily Beretta and Browning ). A big issue is adjustability - and one gun I see, with the most adjustability, that will fit a lot of shooters / and has very good resale value - is the Browning Citori XS Skeet model, with the adjustable comb. They retail new for around $ 3,000 now - but there are some used ones around in both 12 and 20ga.
I'm a big Browning fan - but last I looked in the Citori lineup alone there are about 25 models / and for me personally, only 3 will Fit me properly ( XS Skeet, XS Special, XT Trap ...) so its isn't about just buying a Browning, or a Beretta, Ruger, etc ....its about Fit ( or its a waste of money ).
But what games are you considering ? ( Sporting Clays, Skeet, Trap ...or all of the above ..)....