brushes from deviantart are rarely the way to go. If you want to look like any number of the 12 year olds who have access to photoshop then go for it.
Spend 5 minutes and make your own, if you need spray paint drips your own work is a lot better than anything you can find elsewhere. Also if you're going for simple vector drips and want consistancy with the look, you can always make a simple rectangle and a circle at the end that is the same width to give a graphic effect of a drop. And i shouldn't have to say this, but the more interesting or natural the drip ... the better it looks. .... but do your own design work.