hey new poster needing help

I am actually not a trucker at all, im a college student doing a stock report on Paccar. I dont know anything about trucks, but I would like to know the basics about the basic differences between the companies. Reading the posts it seems like people tend to like Paccar trucks a lot. Im getting the idea that they are the more luxurious trucks or whatnot. But if anyone could give me some input onto what the reputations of these trucks are it would be appreciated. like if you hate one manufacturer let me know. Im especially trying to get a comparison between Volvo, Paccar, Navistar and daimler Chrystler (freighter). Thanks for anyone that can help.