Mr. Moore pointed out the highlights of the major differences. Great job! I appreciate you and the others helping people with their questions. :^) There is one additional major difference and that is the ND's and all other Herpstats have resettable fuses. Which means if you have a power spike, faulty heat element, or decided to try out your 1500 watt space heater on the stat (we get this one alot) the resettable fuses will overheat and shut down. Once unplugged for 5 minutes or so they reset and the device is functional again. On the original herpstat it has a soldered on fuse so if you have any of the above failures it means a shipment back to us to get it replaced. I have recently found a way to integrate a resettable in the original Herpstat however it knocks its wattage down to 400 watts which is still plenty for 99.9% of the applications out there. If someone wanted to purchase a modified one they can email us directly with the request (no extra cost). That being said we sell a ton of both thermostats. As far as bang for buck you can't beat the additional features the ND has. But the original Herpstat is cost effective (if you won't be using night drop) and you can read the display from across the room. :^)
We do everything via email (hence the no phone number) as we are a small company with a handful of employees and I am on the building line too. Anyone with questions can always shoot us an email at
sales@spyderrobotics.com which gets checked throughout the work days and sometimes on weekends too.
Dion Brewington
Owner, Spyder Robotics