I wanted to focus more on the differences between these 2 skis than a full-review. Performance-wise, they are similar; feel-wise, they are very different, and do different things well.
1) Rossignol Soul 7 188cm
2) Blizzard Peacemaker 186cm
Conditions: mostly firmer off-piste conditions over 3 days. Some firm bumps, some softer snow in wide-open off-piste skiing. A smattering of groomers, and random tree skiing.
Skier: 5 foot 9, 155lbs, skis 30-50 days a year, tend to ski fast, rapidly-improving skier that feels comfortable in most any condition. I tend to prefer off-piste skiing, unless on a good hard snow ski: then I like to ski groomers fast arc to arc. Still mastering bumps, but have come a long way, and am getting to a point where I can ski zipper-like pretty well.
The execution on these skis is quite different. One has a pretty standard (for current ski design) camber section underfoot, with similar for industry standards tip and tail rise, and a pretty rounded flex. This ski (the Blizzard) also has a very standard sidecut, not tapered. The Rossi has a similar length camber section, but with more of a clown-shoe design tapered tip, which brings the sidecut feel down. The tip and tail have much taller rise, much more abrupt than the Blizzard. Also, the honeycomb style tip on the Soul 7 has a lower swing weight feel than the Peacemaker.
Overall feel: the Soul 7 is less than classic Rossi; very light on the snow. Flickable, for lack of a better term. Super light, almost like it has the weight of an AT ski. It just doesn't weigh anything, and seems to float, due to the light feeling, between turns well. Almost what one would expect a carbon ski to feel like, but with a more damp character. The Peacemaker is a bit more of a recent Nordica/Blizzard feel: it has similar dampness to the Hell n' Back and Steadfast: which for me, is fairly light and lively, not really heavy on the snow, more underdamped than overdamped. It feels quick, and more alert than the Soul 7. Another way to say it is the Soul 7 feels chill and laid back, but ready to come alive at a moment's notice.
Stability: Both of these skis are designed to be playful, easy to ski, and quick. As a result, neither is super bomber at speed, at least compared to the big brothers of the Peacemaker (Cochise and Scout). The Peacemaker does have a titanium re-inforcement; combined with the longer sidecut the ski feels more at home in big arcs, at speed, and in choppy snow. Not the last word in stability, but decently solid. The Soul 7 was a step below: I easily found the speed limit (and exceeded it) in similar conditions. At this point, I felt I really had to pay attention to the ski and stay balanced; it didn't leave me a lot of room for error once I was letting the ski run. The tip flap is not confidence-inspiring in rough snow. If you are a faster skier, you may want to look at the Peacemaker.
Quickness; another area where these skis differ significantly. The Peacemaker is medium-quick. Not really sports-coupe quick, a little more predictable and big-turn friendly than that, as noted above. Easy to ski in trees, butter if you load the tip; however, it still takes directions from the skier, rather than wanting to always find an edge. The Soul 7 is quite a bit quicker: the different tip profile just wants to engage and bring you around. Super easy to turn, super easy to pivot. Put an intermediate on this ski and they will be blown away at how they can move edge to edge on it. It being such a light ski, there is almost no effort required to change edges.
The feel is completely different too: almost more of a pivot/smear feel, whereas the Blizzard feels more traditional, more locked in, more rewarding to load the tip with. This has much to do with the tip sidecut profile, IMO.
In bumps: Here, the soul 7, rather surprisingly, is super fun. Despite being wide, the tip is soft and easy to press into a trough. The tail is not aggressive. It may be the best wide ski for bumps around. The Peacemaker isn't as good: tail is stiffer, the tip flex is less rounded at the tip, and it makes you work harder. Average for this width.
groomers: I can't say I am a huge fan of either on the groomers: both skis are wide and lack tip engagement; plus, they are not the last word in edge hold. I lean toward the feel of the Peacemaker, and prefer the more traditional tip here. I can adapt to the extra rocker in the tip by simply getting more early edge angle: I have to ski it well to ski it arc to arc, but can do it. The Soul 7 doesn't provide me a lot of confidence to lay it over: the edge grip isn't great, it is pretty soft and deflects at the tip, and has a short running length. I think any ex-racer or otherwise high level technical skier will find the Peacemaker a more suitable ride on the groomers. In softer groomers, the Peacemaker is quite fun. The Soul 7 still feels a little funky and short, lacking power in the tail.
Great skis, but different: I am a fan of both skis. My preference is for the more traditional feel of the Peacemaker: I tend to ski fairly fast, in medium to large arcs, on a bigger, wide-open mountain. Also, I like to rip groomers like I am on a GS ski, and want some energy and a traditional tip to tail feel. The Peacemaker clearly has the edge here. However, if I were skiing new snow tight trees all day, tiring conditions where I wanted a bit of an edge, and also in bumps, the Soul 7 would get serious consideration. It wouldn't be my choice for firmer snow, but in overall softer snow, it has a lot to offer if you need to turn quickly and often. It also is going to be the "easier" ski: the Peacemaker is super easy to get onto edge, but the Soul 7 basically turns itself! That makes it a winner for a lot of people, who frankly could use a little help in tough conditions, as well as those people who just like quick skis.