To add on to the excellent general overview given by user/ShadesOfLamp, I would add that western Europeans were probably the best heavy cavalry, and possibly heavy infantry, in the world at this time. The Muslim writer Bahā'al-Dīn reflects on their ability to shrug off multiple arrow impacts by dint of their combination of mail and padded and/or felt armor.

...drawn up in front of the cavalry, stood firm as a wall, and every foot-soldier wore a vest of thick felt and a coat of mail so dense and strong that our arrows made no impression on them... I saw some with from one to ten arrows sticking in them, and still advancing at their ordinary pace without leaving the ranks.

They were viewed by Byzantine and Muslim sources as hotheaded, impetuous, and ferociously brave, but "uncivilized", and various digs were made at their dress, manners, morals, and hygiene. The Byzantine princess Anna Comnena marveled at the strength and ferocity of a charge of Frankish knights, saying that "a mounted Frank is irresistible; he would bore his way through the walls of Babylon."

The downside to this is they tended to be slower than Muslim armies, which contained relatively few heavily armored horsemen and infantry, and could wearied by them. Here's an example to demonstrate this weakness, this time from Joinville.

...and whilst the Turks were fleeing before him, they (who shoot as well backwards as forwards) would cover him with darts. When he had driven them out of the village, he would pick out the darts that were sticking all over him; and put on his coat-of-arms again... Then, turning round, and seeing that the Turks had come in at the other end of the street, he would charge them again, sword in hand, and drive them out. And this he did about three times in the manner I have described.