I think these guys have said just about everything that could be said to prove that a lowered truck, when done correctly is just a functional as a stock one.
I could go on for hours about the pro's and con's but I won't. I'll simply say if you look at a properly lowered truck and it doesn't make you feel warm and fuzzy inside, then you just don't get it. In other words if you have to ask why, then you wouldn't understand if I told you....