it'll probably cost almost a couple hundred bucks worth out of a rattle can to get it looking good.
You'd be better off getting jugs of it, thinning it, and spraying it with a paint gun. See here:
http://www.e90post.com/forums/showthread.php?t=684511
There are links to the dip site for product sourcing as well.
from a durability standpoint, i think it's pretty nice. I dipped the bottom of my rear clip as i wanted somehting that matched to motif of the carbon, but i know rocks and shit hit it all the time and i didn't want to have to re-wrap the whole bumper if it got chewed up. I've never had to respray that area and there is constantly gravel and sand and stuff hitting it and caked to it. originally, it was made to dip tool handles in to give you a better grip. that's what it's called plasti-dip and not -wrap-in-a-can. So knowing it's use, I dont know why people think it just falls off on it's own or something.
As far as comparing it to a wrap cost-wise... that comment must be a joke. I wrapped my car and it was almost 1k in material alone. granted it was di-noc and matte black is about %40 cheaper, but that's still way more expensive that plastidip. and then you gotta pay for install unless you know what you're doing.