Go Power took its time to create a great 12 volt MPPT charge controller. Here are my findings after using the controller for a couple weeks.
The controller is well laid out and the feature set creates a robust offering for 12 volt charging. The battery cables are split to allow for smaller gauge wires to be doubled up to the battery bank
Stacking the charge controller is easy and powerful. Go from an existing 40 amp system to an 80 amp system in just minutes. All using the same MPPT charging profile. This makes easy series parallel configurations for larger arrays. Simply double up 4 panels in series on each controller to maximize output.
We noticed an amperage discrepancy when using dissimilar panels when operating. This I think is pretty standard, but worth mentioning.
We sell these units, but we also use them. All in