How and when to use Ripridders?

They are quite underwhelming from my experience. They take a lot of space and honestly don't fare well against high-numbering heavy units. You can have more of speartons and juggerknights than Ripridders, so late-game my army of Ripridders + Eclipsors got pounded badly by an army of speartons. What would be a good combo for Ripridders and how does one play them optimally?