One. Fulcher of Chartres (First Crusade): "Oh, what an excellent and beautiful city! How many monasteries and how many palaces there are in it, of wonderful work and skillfully fashioned! How many marvelous works are to be seen in the streets and districts of the town! It is a great nuisance to recite what an opulence of all kinds of goods are found there; of gold, of silver, of many kinds of mantles, and of holy relics. In every season, merchants, in frequent sailings, bring to that place everything that man might need. Almost twenty thousand eunuchs, I judge, are kept there continuously.

[...]

"It was necessary for all to confirm friendship with the Emperor, without whose counsel and aid we could not have completed our journey, nor could those who were to follow us on that same road. To these, then, the Emperor himself offered as many coins and silken garments as he pleased; also some horses and some money, which they needed to complete such a great journey." The First Crusade: "The Chronicle of Fulcher of Chartres" and Other Sources, edited by Edward Peters, page 62.

Two. The writer of Gest francorum was anonymous but connected with Bohemund of Antioch (First Crusade). It describes the Byzantine emperor as "evil." http://www.fordham.edu/halsall/source/gesta-cde.asp

Three. Peter of Cluny to the King of Sicily urging an attack on the Greeks for the betrayal of the Second Crusade: "Furthermore, we make known to your royal majesty that we greatly lament the conflicts that are going on between you and the lord King of the Germans (or Emperor of the Romans). Both I and many others are strongly of the opinion that this discord is harmful to the Latin kingdoms and to the Christian Faith. For we have heard many times and often how your military power has brought benefits to the Church of God in the lands of his enemies, that is those of the Saracens. Moreover, we believe that greater advantages would accrue if you and the aforesaid king were united in a lasting peace and concord. There is also another matter which has long been of concern to us, and to almost all of our fellow countrymen in France, in seeking such a peace for you; namely the wicked, unheard of and disgraceful betrayal by the Greeks and their miserable king of our pilgrims, that is those in the army of God.

"I shall speak of what I have in mind. If it should be necessary, insofar as is appropriate for a monk, I would not refuse to perish, if the justice of God would, through the death of one of his servants, revenge that of so many men, both nobles and commoners, indeed the flower of almost the whole of France and Germany, destroyed by wretched treason."

This link also has a range of sources by Westerners damning the Greeks for betraying the Second Crusade. http://courses.ttu.edu/jhowe/Source_Problem_II.htm

Four. Odo of Deuil (chaplain to Louis VII during the Second Crusade): “The Greeks [...] closed their cities and fortresses. [...] Therefore, the pilgrims, unwillingly [...] procured supplies for themselves by plunder and pillage.

"Some thought [...] that [it] was the fault of the Germans who preceded us, since they had been plundering everything.

"We do not want to and cannot depreciate our fathers’ renown, but events went more easily for them than they have thus far for us. For when they had passed through Constantinople and crossed the Arm, they encountered the Turks immediately and entered their lands [...] Instead of the Turks, however, we met with the wily Greeks, whom we spared, to our bad luck, as if they were Christians [...]

"How will a just judge, either God or man, spare the Greek emperor, who by cunning cruelty killed so many Christians in both the German and French armies?" Berry, Virginia Gingerick (editor and translator). Odo of Deuil. De prefectione Ludovici VII in orientem–The Journey of Louis VII to the East. London and New York: Columbia University Press. 1948. http://rudar.ruc.dk/bitstream/1800/4641/1/Final%20project1023.pdf

Five. Robert of Clari (Fourth Crusade): "Then the bishops preached to the army, the bishop of Soissons, the bishop of Troyes, the bishop of Havestaist [4] master Jean Faicette [5] and the abbot of Loos, and they showed to the pilgrims that the war was a righteous one; for the Greeks were traitors and murderers, and also disloyal, since they had murdered their rightful lord [they had just killed Emperor Alexios IV, whom the crusaders had supported so that they could get paid], and were worse than Jews. Moreover, the bishops said that, by the authority of God and in the name of the pope [the pope had actually written numerous commands to the leaders of the crusade to cease attacking fellow Christians, and he had excommunicated a number of them for not doing so. These letters were kept from the army. The pope would change his mind after the success of the siege.], they would absolve all who attacked the Greeks. Then the bishops commanded the pilgrims to confess their sins and receive the communion devoutly; and said that they ought not to hesitate to attack the Greeks, for the latter were enemies of God."

A lot more in the link including from other views during the Fourth Crusade. http://www.shsu.edu/~his_ncp/1204.html

Six. For a Byzantine view, Anna Comnena has much to say about the Crusaders. http://www.fordham.edu/halsall/source/comnena-cde.asp