I believe there are four advantages with an aquaero over a quadro or octo:
- 5-1/4 bay display (if desired, else the LT version)
- calitemp - only the aquaero can do calitemp
- hard virtual sensor - only the aquaero has hard virtual sensors (4).
- option to voltage control fans - quadro/octo only have PWM
The quadro/octo can use the aquasuite virtual sensor (more powerful), but the aquacomputer services must be running in the background.
The aquaero does not require the computer services to be running to implement a virtual sensor (i.e delta-t between coolant and room ambient).
The four calitemps you were thinking of using would require an aquaero with
aquabus X4 for aquaero
There is a mounting issue with the aquabus X4 if you plan to use 4 aquabus X4 ports on a 5-1/4 bay mounted aquaero
(see this thread). you would need to mount the aquabus X4 off the aquaero with a short cable, or the aquaero LT version would be OK.
Bottom line, for your situation, with Linux, you may be best served with an aquaero.