Why pay more for less?
The Helix looks great when built into a rack but other than that it needs a stand. It holds 500watts and is only proportional. The probe cord is only 4ft long.
The VE-300 looks great alone and it stacks. It holds 700watts and does both on/off and proportional. The probe cord is 10ft long.
The only thing that going to beat the VE when looking at price per features are the Herpstats.