I prefer DC because I like their characters, mythology and history more than marvel's. But i don't have a fixed pull list (all digital), so there are months in which I buy more DC, other where I buy more Marvel. Right now, Marvel has been having more stories in which I'm interested, but this is all cyclical.
Also, I can't say I care for Marvel characters as much as I do for DC's, so this factor into me not being disgruntled by them as often.