I skied the CS70 in a 175 and a 165. I'm 5'8" 155lbs, and my ski of choice has been a Head XRC1100sw in a 170 at Bear Valley, CA.
Full notes below, but I got to say I was very impressed by this ski. It's got a TON of pop. Viking9 is right about the edge grip, although I had trouble on the 175 (too much ski unless I was skiing mean). These are TOTALLY different from CX80, not only due to SL vs GS, but I found CX80 to be quite skiable at mellow or warp speeds.
Rossi Classic 70 (CS70), 175cm R13.9, SC124/70/112
Bear Boogiex2, Porridge
Way more than I expected - this is a serious ski. Hard to turn below about 20mph – just did not respond to slow-speed turns: gentile knee angles or even more energetic unweighting or jump turns just felt heavy. Pretty clear it was jut too much ski for me, BUT once I got it up to speed, probably 20-30 mph, this ski tossed me like a mini-tramp! Snap out of turns had huge energy, but nicely predictable – just what you want. I had a blast alternately popping the skis back and forth on quick short arc turns, or flinging myself across the slope if I loaded them up on a longer arc Skis would fly across from one side to the other, and get loaded up again. Very quick edge to edge. Put my Heads to shame at these speeds, and with this energy. No way I could ski this ski all day, but in a shorter length... (see below). Had trouble getting an edge on ice, but that was probably because ski was too long for me.
Rossi Classic70 (CS70), 165cm 165cm: R12.3, SC124/70/113
Face, Grizzley Facex2
Last ski out was the CR70 in a 165. This was a totally different experience than the 175 for 2 reasons. First, they are very different skis (length, but also radius and amount or type of metal according to tech), but probably just as importantly, conditions were completely different just 24 hours later. Sky had turned lake-blue. Sun was beaming, and had completely thawed the bioler-plate. Snowboarders going shirtless. Pole plants were now bottomless, and the bumps were growing. Took them down a couple different bump runs and a bit of crud and untracked cr**. Awesome in the bumps, as expected. A bit of a challenge in the soft stuff, but torsional stiffness would keep them tracking straight regardless. Responsive and lots of pop meant it was pretty easy to get some air time between bumps or on a couple of airplane turns (again, the soft snow helped!). Biggest challenge in these conditions is short length meant for-aft balance was more tenuous, especially when hitting something softer, wetter, or stickier than expected. Think this was not quite as versatile as my XRC-1100 - not as stable at high speed or a s comfortable with long radius arc. The CR70 also wanted more energy input, but it was close. In a 170, it might be VERY close. Why should I get this ski? I got an anonymous high-five at the end of my last run by a guy in the lift-line who said I was ripping it. Thanks Rossi!