So, with the upcoming release of DoM, this could soon be outdated, however, in the New Shadow, I've found Riddermark Spears to be underwhelming. If I charge a (fairly average) army of Dunlendings, I find any single unit of Riddermark Spears loses a lot of men for little profit. When going towards the enemy, archers will take 5 or 6 of my men (on ultra unit settings). On hitting the enemy I'll lose maybe another 10, only once have an enemy unit broken on being charged by my cavalry, otherwise I'm choosing between letting my men remain in melee, losing men at an incredibly fast rate now, or retreating to charge again, losing another 20 or so as throwing spears and arrows catch them from behind. So, if my men remain in the melee, they'll be useless for another battle, whilst if i withdraw to charge again, I find that a second or third such charge reduces them to such an extent they also become fairly useless.
I don't have such an issue with the Riders of the Mark, who I've found to be almost as effective in the charge and far superior in the melee, with increased arrow resistance due to their shields. Do other players find this? Presumably I'm not using them in quite the way they're intended, however I've never had a problem in the original Rome or other mods for Rome/BI/Alexander, just as I don't have an issue with other factions (in the New Shadow) elite cavalry.