While you can shoot Skeet, Trap or Sporting clays with virtually any gun you can hunt with....pump guns, while they are on the less expensive side of shotguns, are not optimal for clay target games.
But nothing wrong with a good pump gun - say with a 28" barrel ...as long as it has changeable screw in chokes - so you can optimize your pattern for the games you want to play.
My pump gun of choice is Browning BPS Hunter model ...good solid gun --- ejects out of the bottom - so its good for a leftie or right handed shooter --- its cast neutral - so again good for leftie or rightie -----and safety is on top of the tang...where its easy to reach, even with gloves on.
BPS Hunter model sells new for around $500 ....so they are more expensive than either pump gun mentioned above ....but I'll tell you the actions are smoother in the BPS than most anything made by Mossberg or Remington - with the possible exception of the Remington 870 Wingmaster which is their higher end pump gun vs express models, etc... / but I see guys every week at my club shooting skeet with good solid pump guns .
I shot Trap singles for many years with a Browning BPS Hunter model ...and while you can train - to operate the pump and still maintain contact with your shoulder - and your face on the comb - as you cycle the pump its probably not the best long term option.
advantage of semi-autos for clays... / cycle quickly, light guns for the most part, gas operated means less recoil than any fixed breech gun like a pump or O/U. Downside....you have to pick up your hulls all over the place ...and you only have one choke (one barrel). Some of them can be finnicky on shells..resulting in jams ...and maybe lost targets.
Advantage of O/U's ....2 barrels, so 2 chokes if you need them ----no functioning issues from cycling...if you can get the shell in the chamber and close the gun - it'll probably fire that shell -----less moving parts so in general they're going to stand up to more shells over time ----- better triggers in general -----