Depends on the period. Obviously a Late Medieval guy in full plate and on a plate-barded horse has way more staying power than his Early Medieval colleague with just mail hauberk (tops) and "buck nekkid" horse...

But in general terms knights would be "high speed/high offense/moderate resiliency/high charge" type while catas would be "low speed/high offense/high resiliency/moderate charge" IMHO (I personally don't like the way knights were the about only cavalry in MTW whose Attack was above "good"). Knightly armour improved of course, but then again the other "Eastern" cavalry school was that of high-maneuverability heavily armoured guys practicing a kind of hit-and-run approach - charge in, do some damage, disengage, regroup, rinse and repeat until the other side breaks. AFAIK the massed catas employed as a ranked-up battering ram were a bit of an unusual variation around those times, and probably primarily meant more to disperse massed heavy infantry than for all-around battlefield use which demanded more flexible formations.

Curiously enough though, the Gothic Knights of MTW are really "massed cataphracts" in overall design - designed more to hack the enemy to bits over a sustained period partly by virtue or raw staying power rather than the usual shock charge duties of knights.