User blog comment:Leolab/Lancer (Fate/Zero) v Lancer (Fate/Stay night)/@comment-422690-20150314181608

Note: I'll be referring to Fate/Stay Night's Lancer as Lancer, and Fate/Zero's by his name.

So...

Skills: Diarmuid has two skills that will be useful, namely his magic resistance and Eye of the Mind (True). The magic resistance will slightly offset Lancer's Rune Magic, giving him some protection. His Eye of the Mind (True) will also let him react and easily determine the best possible course for victory. The only actual skill that Lancer has that will have an effect is his Battle Continuation skill, which will prove to be a major asset. He's been shown to be able to hold a coherent conversation with most of his left torso missing, letting him fight on even when dealt a fatal blow.

Weaponry: Gae Bolg is slightly longer than Gae Dearg, as Lancer fights using two spears. Diarmuid has the potential to have greater agility, which - combined with the unpredictability of his dual-wielding style, will give him a slight advantage here.

Noble Phantasms: Right off the bat, Diarmuid has an advantage in terms of noble phantasms. His are activated as passive effects, meaning that not only does he opponent have no warning, it doesn't drain his mana. Not only does Lancer need to call out his phantasm's name, he tends not to use it unless sorely pressed. It has a far more powerful effect, one that Diarmuid's luck stat is too low to dodge, but it's also highly likely that he won't use it until it's too late to do him any good.

Overall: Overall, Diarmuid's the better combatant here. Despite his disadvantage in terms of skills, he's more able to use his trump cards - the Noble Phantasms - as well as more willing to use them.