I prefer Spyder Robotics Herpstat to Helix. But it isn't that much less expensive. My Helix DBS-1000 went wacky once when it was controlling two large racks. The racks didn't exceed the 500W rated load of the Helix, but it screwed up anyway. I now have that controlling a single rack, a Herpstat controlling another single rack, and a second Herpstat controlling two large racks. The Herpstat controlling the two racks has been consistent and reliable.