The first reason is because they can have terrible problems with heat mirage. I've never had trouble with it, except with my SxS at the range. Barrels heat up, hot air scrambles your sight picture.
Regulation isn't such a problem; some really cheap SxS seem regulated okay these days. Cheap O/Us can be just as bad, too.
SxS aren't necessarily lighter. A lot of 12 Gauge SxS guns, generally the cheap ones, are heavy, and in the wrong ways. As a result, they feel like absolute crap to swing.
If they have a lot of felt recoil, it's more likely because of the stock drop than the weight. Some have a LOT of drop. This is incompatible with range shooting, generally, not just because of recoil. It can work great for doves flying right over you, but not much else.
The sight picture (until the barrels heat up) isn't necessarily a problem. It can be quite intuitive, with the rib between the barrels. The SxS can tend to favor vertical motion over horizontal, though. A well-balanced O/U or semiauto can swing very naturally on skeet targets.
You can get a pretty nice used O/U for a grand. Avoid the Browning Citori and all other guns that lock up under the monoblock, and you can get excellent pointing characteristics. The Browning Cynergy, Berettas, SKBs, etc. can "feel like a SxS".
You can also get a
world-class semiauto for a grand, brand new.
A SxS with choke tubes? You're going to sacrifice that nice handling you want, and/or the longevity you need for range use, if you want to get the thing at that price. And it still won't work as well. There's a reason that I've seldom ever seen a SxS at the range, and it's not because everyone is smoking crack.
Is there any way you can do some trying before you do your buying?
One's notion of "aesthetically pleasing" can change rapidly, when you bust a bunch of difficult birds, or, conversely, when you miss a bunch in a row.
If you can try various guns, and you still really want a SxS, nothing will stop you from getting it (except that you'll want to spend more than a grand
).
Note that Beretta makes SxS field guns, and high-end "premium" SxS guns, but they don't make ANY competition SxS shotguns. It's not because they
couldn't. They make a lot of O/U and Semiauto competition guns.