Hey Cito,
The ProProduct HP, are the best in my opinion on the market bar none. I know that Robyn has had some burn out on him and has had some problems trying to get them to cover either the replacement or the reimbursement of the product in question. However, I've spoken to Bob over at ProProduct, and he has assured me that the HP's, have been improved and have been corrected to where the old problem that Robyn had experienced, is no longer an issue.
I would definately go with the ProProduct, but that's just me being biased and not really knowing the Helix product (HP) as well. I do love their Thermo-controllers (DBS1000, Basic) a lot and wouldn't use any other. As for the question you asked about whether the heat panel would be enough to heat a cage, believe you me! there is nothing more reliable than these products for heat. They put out more heat than you can imagine. I however, would not sit the thermostat probe on the cool end like someone else described, as the temperatures you want to control are right under the heat panel (the heat can spiral out of control). The heat will cool off some by the time it reaches the other end (creating a gradient), and will keep the other half within a marketedly high temperature relative to the hot spot under the heat panel. I have mine reading 88-90 under that heat panel and on the other end it reads in the low 80's.
Anyhow, hope you find what you are looking for and figure it out sooner or later.
- Angel
-----
Sometimes on your way to your dream, you get lost and find a better way!