I have owned a pair of s510s and the fathom 113s. JL for HT and REL for music is an oversimplification people should dismiss. Their setup philosophy and feature sets are very different. REL assumes good in-room bass response from the main speakers. Their "advanced" setup asks the user to flank the main speakers with their subs and minimize the filter and volume. The placement adjustment pends a listener version of an impulse response. Their features are limited, but I agree the polarity switch is more essential than a phase knob.
JL Audio’s feature set is 100% about in room frequency response. Because of their electronics delay, I believe coincident impulse response between their subs and the mains is not happening without a digital crossover. I am not so sure about REL, either way. This is because of the poor frequency response in my room, it was worth trying. In theory is difficult to imagine solving for both frequency and time at just by room placement.
REL has other advantages like lighter weight and lower entry cost. I believe their website’s sub-speaker matching is terrible. There is no way a T9 pair would match my 4367s.
Based on my experience I think one will more likely get away with REL if the in room frequency response of the main speakers is already good. JL Audio works better for me. If bass frequency is off enough and bass decay is extended enough, a more power feature set may be warranted.
To clarify an above post. The CR1 has no EQ. I personally set up every parameter as best I can before running DARO.