Two Class Cs that have not been mentioned that I think are higher than average quality are Dynamax and Renegade. The question asked by the OP was "Best", not best value.
Born Free and Lazy Daze are also very good, as previously stated
I have no experience with Magnum. This past year, I had a solar system installed, and used that as an excuse to switch out my Xantrex system for a Victron full system. So far, so good. Have had no problems, so no experience with their support..
I had to wrestle with limitations in space vs paranoia over water quality. Ended up with a 5 micron sediment filter, 1 micron carbon block, and a UV filter. All water goes through the system. System gets purified once a year. Works for me.