Being a traditionalist, I find the gracefull lines of a straight gripped (English style) SxS to be the most aesthetically pleasing,
From a pratical side, the SxS shape gives the foreend hand a nice triangle shape to hold on to and the straight stock seems to somehow prevent overshooting.
I had shot other SxS guns and had some difficultys learning to sight downthe rib but since buying a Stoger 20ga double with a CORRECTLY fitting stock I no longer have any issues with that!
Proper stoxk fit is paramount in the selection of a gun no matter what it's intended use! I found mine by dumb luck but I suggest that you take a learned pal with you while shopping for yours.
If you were weined on a pump or semi-auto, perhaps an O/U might be best for you. It gives but one sight plane to look down and simulates a pump/ auto.
Again look for stock fit.
Try to envision what clothes you will be wearing because a heavy jacket can require a shorter LOP.
I have read of troubles with single trigger SxS's Check into that...
HTH
ZVP