It's definately possible to ride switch and land switch. Is it as easy as some other skis, i doubt it. I dont ride seths but it seems they have a wide nose
the further forward you mount them the better they ride switch. My last pair was at 2cm back of true center and they were much better than the pair I had mounted in the recommended lines, with regards to going switch (and being a mostly east coast ski). Seths mounted close to center do however ski powder with a bit more effort than a traditional mount. I'd say it's a matter of degree and how much you value switch performance.
i have mine mounted 4 back from center and they're sick. a couple cm forward and they'd be dialed for park. the SV kicks ass everywhere you go- powder, park, or pipe.
not sure how much the deminsions have changed from model to model, but i centermounted some pistols, and they still perform adequate all mountain. i dont think i would have done it if i didnt have other skis for the deep days, but the pistols spin easy and do fine on the metal and all that. front and backwards.
mine do fine, and i ski in utah... so i figure if im getting decent float here on them, they will probably do fine anywhere. plus, im 6'6'' and like 200lbs... theyre really nimble in tight spots with the center mount too.
i will say though, that on a deep day i take out my madens... but the pistols do fine too.