The VCT line has always been backcountry oriented an the EHP line has always been big mountain oriented. Backcountry and big mountain skis are similar in terms of their dimensions (wider is better because it provides greater stability at higher speeds) but quite dissimilar in terms of their stiffness (softer skis make less technical skiing such as powder/untracked easier whereas stiffer skis are a must have in highly technical - potentially icy/wind affected conditions).
As people have gotten used to wider skis underfoot, the VCT in all lengths and the EHP 190 have become an excellent every-day skis, both in and out of the resort, at least west of the Mississippi. In Utah, we have a lot of people who make their "backcountry" ski into their everyday ski. Models like the EHP 190, the VCT or the Volkl Gotama make that possible because their design accommodates performance in a variety of conditions. Skis like the Hellbent or the Pontoon, on the other hand, are so specialized that they really only perform well in very specific conditions.
The choice of the VCT 189 or the EHP 190 really boils down to two considerations: first, how long of a ski do you tend to ski (although the skis are onll 1cm different in running surface length, the EHP 190 is 3.5cm longer in effective edge, or the amount of the ski that is engaged during normal skiing) and second, how stiff do you like your skis (the EHP 190 is sitffer (less forgiving) than the VCT 189.
I hope that helps clarify the differences.