With higher voltage, the expense to control the amps is less, because controlling amps is expensive.
A commercial controller still has the added features.
In a small system, they are usually not very important.
In a larger system many other factors should be considered.
Is the system usually operating with a low battery, or floating.
Is the average output 100W or 500W.
Is the operator aware of all the limitations and knowledgeable about battery care.
A good commercial controller makes these things less important, because the controller should be smart enough to recognize and deal with some of the issues, even if the operator is not.
My recommendation for a 800W system would depend on how it is operated, and who is operating it.