I've never ridden any RockShox - usually cos they have been broken
Personally, I'd not buy RS or Manitou for that reason; over the years I've seen so many fail, rattle, fall apart or stop working that there's not a barge pole long enough for me to touch them with.
On the other hand, I do know people who like them.
Magura just seem to keep going (like the old style Marzocci or Fox) and work well. The double arch does seem to boost the steering accuracy too. Shame Maguras are so pricey now.
Weight wise, the RS are probably lighter. But if they've stopped working...
Hoe do you find the Genesis rigid forks on your Giant? I'm tempted to go rigid in the winter, summat like the Pace RC31's
Aging faster than I ride.