I have few primary source excerpts that could shed some light into this question. However If you wish to just get my opinion on the matter you may skip these excerpts and come to the last paragraph. First is from Fulcher of Chartres "Some of the latter, Arabs as well as Ethiopians, fled into the Tower of David, and other shut themselves up in the Temples of the Lord and of Solomon. In the courts of these buildings a fierce attack was pressed upon the Saracens. There was no place where they could escape our swordsmen. Many of the Saracens who had climbed to the top of the Temple of Solomon in their flight were shot to death with arrows and fell headlong from the roof. Nearly ten thousand were beheaded in this Temple. If you had been there your feet would have been stained to the ankles in the blood of the slain. What shall I say? None of them were left alive. Neither women nor children were spared."^(1) This is a detailed account of siege and fall of Jerusalem. So you may say that we are up to a bad start. However as it is with all holy wars there are major hostilities towards one another at the beginning but only up to the point where the new conquerors realize that earth must be toiled and taxes must be collected which then in turn becomes a less hostile living conditions where even a glimpse of tolerance can be observed. Of course there are several different opinions on the Crusaders from ocuppied Muslims ranging from curiosity to rage^(2). Second excerpts are from Usama Ibn Munqidh and written in a tone of an alien encounter:"Among the Franks are those who have become acclimatized and have associated long with the Muslims. These are much better than the recent comers from the Frankish lands. But they constitute the exception and cannot be treated as a rule. [...]" ^(3) and another passage from same excerpt "The Franks are void of all zeal and jealousy. One of them may be walking along with his wife. He meets another man who takes the wife by the hand and steps aside to converse with her while the husband is standing on one side waiting for his wife to conclude the conversation. If she lingers too long for him, he leaves her alone with the conversant and goes away."^(4) These excerpts show us that there are no strict boundaries at least between Muslim nobility and Crusaders. However throughout Munqidh's and Fulcher's memoirs there are no mention of peasants or peasantry at all.

My guess is that as it is always in the case of conquest and empire building, with each new war effort from either Muslim or Christian, this empire or that empire, this nation or that nation a great deal of conscripts and peasants were killed in the initial offensive, however after the boundaries are set the peasants were out of the picture again as it is always: In nearly all middle-eastern cultures while peasants and local elites remain same while the ruling class changes^(5) constantly between different rulers. Hence I would argue that it was no different at all, just different names for rulers and different names for taxes but peasant's status as "second rate human" that toils the earth, crushed under the burden of the taxes, starved from constant warmongering was always the same. Also to mention the relationship between conquered elite and conqureors, it was same too: business as usual.

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1- A History of the Expedition to Jerusalem, translated by Frances Rita Ryan; edited by Harold S. Fink (Knoxville, 1969), pp. 271-2.

2- All excerpts are from Muslim Scholars since peasant's hardly had enough time, leisure and education to write about themselves.

3- An Arab-Syrian Gentleman and Warrior in the Period of the Crusades. Memoirs of Usamah Ibn-Munqidh, translated by Philip K. Hitti (Princeton, 1987), pp. 159-171.

4- Ibid.

5- See: Amir/Ayan Systems.