Originally Posted by ThunderstruckStudios
I second that.
"Thirded", although if the application isn't critical / you have other sources of power and you're willing to experiment... there's always cheap gems to be found out there.
Sounds like you're looking to make your money matter however, and not knowing your budget my recommendation comes down to two choices:
#1 : Victron Energy's MPPT Controllers (I have their 150V/100A, but smaller versions exist)
These guys do alot of embedded systems work with their controllers and so there's quite of bit of easy-to-use, pluggable functionality for their product line. Alot of them have bluetooth and data logging out of the box. I can see my daily yields in a bar chart on my phone, its nice.
I'm using mine on Lithium (Tesla) batteries but they support anything really. Fully configurable Bulk/Absorption/Float voltages with sane presets.
#2: Renogy 40A, 60A MPPT charge controllers
I have a 40A Tracer Renogy controller which was my first serious solar controller. Still have it and the AGM batteries for it, not sure what I'm going to do with them now, but this has been rock-solid for me in both 12V and 24V configurations.
Mine ran outdoors for two years with zero issues. Still works, its a tank. Whether or not I reintegrate it will depend on the practicality of making the two heterogeneous systems (AGM, Lithium) work together.
No links because both sets of options are fairly easy to find.