I skied the Rocker2 on Saturday at Killington. Conditions were: pretty cut up snow (14" on Friday and another 2" or so throughout Saturday; some fresh in woods (if I had gone in there). Cut up: sure; aweome: definitely!
I've never tried the S7, so I can't compare them, but here's what I thought of the Rocker2.
Me: 240 w/ gear; Level: made it down Outer Limits w/o too many problems.
Initial impression: This ski is FAT.
I demo'd the 184 from Basin Sports (they seemed like alright dudes; to be fair, on Friday I demo'd a Volkl Bridge from Northern Ski and they were cool too). The Bridge was a narrow SL in comparison...I know it says 122, but the 142 in front makes it look HUGE.
Back to the program: The widest ski I had ever been on was the P-100 and this was substantially wider; I was even a little nervous at first. Did I mention they were WIDE? They didn't fit in the ski holders on the bus; they didn't fit in the gondola holders (I used two snowboard slots).
Skiing: Killington skied awesome; despite my limited knowlege of the area, I would say that Killington doesn't ski much better than it did on Sat/Sun. The best runs were black diamond (especially Northstar); runs like Double Dipper and Cascade got scraped off pretty quickly and left dirt, rocks, and ice despite the new snow (although Outer Limits was perfect/Devil's Fiddle was closed).
Rocker2: Performed admirably: after a few runs to get used to it, I took it everywhere (except the woods). The bumps were perfect and the Salomon did well. Groomers: no problem at higher speed (I even got them carving); when I went over some scraped off icy spots, they held OK. If I had gone in the trees, I could tell you that they surfed around and were fun...but I didn't.
Verdict: I had a lot of fun. Partially b/c of the conditions and partially b/c the Rocker2 is a fine ski. HOWEVER, I don't think the Rocker2 has much business being out on the east coast; sure a bunch of people are going to tell me that I'm wrong, but that was my impression. If I lived where you regularly get 2-3' dumps (or 14' in a week period), I might be saying, "Go get yerself a pair of these; they're pretty awesome!" ...but,
The Volkl Bridge (179) was where it was at. In the 14" of fresh snow it ripped. In the woods (where, again, I didn't go) it would have ripped even over a 5' frozen waterfall that I did not go over). In the bumps it ripped...on scraped off ice, it did well.
Final say: You said you wanted a good powder ski. I guess I would ask how much powder. I think the Rocker2 is a fine ski and had fun on it; it performed well in everything I threw at it...but, I think there's better options when the snow isn't as deep...the Volkl Bridge was much better (to me). If there was 3' of fresh, I might have felt differently.