Interestingly, I have both the Stöckli 172cm WRT and the 177cm SC, as well as the 185cm Laser GS, along with some 165cm FIS SL’s and 183-188cm 21-30m radius Masters/FIS GS skis.
Over the Holidays I had some spare time, so I tested the above skis back to back at Squaw--free skiing on west coast “hard surface” groomers (probably equivalent to East Coast powder), a variety of bumps, a few inches of fresh, as well as some cut-up mank. Keep in mind I am a 6 ft, 210lbs old guy who grew up racing straight skis and has a more "directional" style.
A lot of my thoughts are in concordance with what has been said earlier in this thread, but some will differ.
Each of the Stöckli’s in question—WRT, SC, GS are among my favorite recreational carving skis, although if I could only have one of them, it would probably be the SC. I find each of these Stöckli’s to offer easy turn initiation over a wide range of speeds, great edge grip on almost all surfaces, good rebound energy, larger than average sweet spots, and a greater degree of forgiveness than many other similar caliber skis.
In my experience, one simple observation has been that folks who enjoy a FIS SL will like the WRT, while those who don’t appreciate a FIS SL are more comfortable with the SC.
I have previously written about my experiences with the SC, but to recap, after moving the bindings forward 1.5cm, the SC turn shape can be varied from nearly SL tight to almost GS wide on surfaces ranging from icy hard morning groomers to soft afternoon slush. The SC is quite fun in both firm and soft moguls. It can also handle a few inches of fresh snow without issues. Turn initiation on the SC is as easy and intuitive as on my 177cm Head SuperShape Rally, but the SC is smoother and has a much higher speed limit than the Rally. In addition, the SC has a very large “sweet spot” and is equally forgiving as the less capable Rally. The Head 177cm SuperShape Speed is closer in top end performance to the SC, but the SS Speed is not as refined or smooth. On my feet, the SC offers a wider performance range than other sport carvers like the Atomic Redster, Nordica Spitfire, Völkl Deacon and others of that ilk. The SC is not quite as precise, scalpel-like, or powerful as the Head e/i.Race or Stöckli WRT for that matter, but the SC is much more fun and adaptable to a wider variety of conditions and terrain. In many ways the SC offers similar versatility and capability as my 181cm Rossi Hero Elite Plus Ti, although the Rossi has a bit more energy, while the SC is more elegant (maybee ZR1 vs. 911). The on-piste breadth and ease offered by the SC is surprising—I suspect both experts and strong intermediates will find the SC a joy carving up groomers, as well as zipping bumps, and roaming all over the mountain on-piste. If you can handle a Head Rally or Liberty V-series, you can manage an SC.
The 172cm WRT is somewhat similar to the 170-175cm Head e/i.Race, particularly in turn shape, although the WRT feels even closer in energy, edge grip, and quickness to my 165cm Rossi FIS SL. When I am on my game, I actually like my FIS SL in the bumps and unsurprisingly the WRT also works well for me in moguls. Like a FIS SL, the WRT is definitely quicker, offers more precision, and demonstrates a bit higher speed limit than the SC. However, the SC is palpably more versatile, has a greater tolerance of errors in technique, and handles a broader breadth of on-piste terrain all over the resort. Note that while the WRT is quite stable arcing turns at high velocities, it can also be whipped around at slower speeds without much effort. FWIW, after experimenting back and forth, I ended up with the WRT's mounted on the line. In short, the WRT is very much like a FIS SL, but with a bit wider turn radius and a touch gentler manners. The WRT's are a blast to cruise around on! Now to burst a few bubbles: At no time has the 172cm WRT ever felt as smooth and stable in longer turns as a 20-30m Masters or FIS GS ski. For that matter, even pseudo-GS sport carvers like the 185cm Stöckli Laser GS or 180cm Head Rebel i.Speed offer better long turn capability than the 172cm WRT. For me, the 172cm WRT definitely feels more like a slightly larger radius FIS SL and not at all like a GS ski--be it FIS, Masters, or Sport.
As recently noted in another thread about my 185cm Stöckli Laser GS; after moving the bindings forward 2cm, I have fallen in love with them for medium and long turn sport carving. They have easy turn initiation at all speeds, feel silky smooth, are stable and grippy on hard surfaces, but can also bust through loose crud. The Laser GS obviously offers a very high speed limit, but they are also surprisingly easy to ski and turn when going slower. Unexpectedly, the Laser GS was able handle about 12" of fresh snow and were also reasonably well behaved in moguls--hmmm, almost an all mountain ski. I like the 185cm Laser GS so much that they have replaced my 182cm AX's, much like I prefer my 177cm SC to the 175cm AX.
I find the Laser GS to be a great complement to my SC's.