The iPeak 90 is an all mountain ski with a bias for off piste use. Its a bit softer than the 84/78 (less metal or no metal, not sure which). Works great in pow, crud, and bumps. And carves nicely on groomers. This is one of my favorite skis in the last 2 years of demos. I tested this ski in a 177.
The iPeak 84 Pro is stiffer with more energy evident at the release. Its also does fine in pow, crud, and bumps, but not quite a well as the 90 for deeper pow and crud. It is better in bumps and it absolutely rips on groomers. I tested this ski in a 177.
The iPeak 78 Pro is the same layup as the 84 but with a bit more sidecut. I did not ski it but I'm told its skis like the 84 but a bit more nimble.
If I wanted a ski primarily for off piste I'd go with the 90. If I was looking for a 50/50 split I'd consider the 84. If I wanted mainly a front side ski that can still perform well off piste then the 78.
Dawgcatching (I have been buying from him for years) is blowing these out at the following prices.
Head Peak Pro 78 flat $360 170/177/184
Head Peak Pro 78 w/binding $455 170/177/184
Peak 84 Pro flat $420 170/177/184
Peak 84 Pro w/binding $510 170/177/184
Peak 90 flat $375 170/177/184
Shop number is 541-593-2453, or you can email Scott at thunderball23@hotmail.com