Sheesh or Yeesh?

I noticed that my blog tag widget displays both "sheesh" & "yeesh." I did not realize I was using them interchangeably, so I researched these interjections and discovered they are indeed related. 

Several sites declare they are both used to express "annoyance, disapproval, dismay, surprise, impatience or distress." The urban dictionary explained that yeesh is "yikes" and sheesh combined and etymologically they are variants of the exasperated expressions, geez/jeez (and their profane origin)...or, at least that's the hypothesheesh. ;)

Either way, I love them. 

I checked my tag stats and discovered I use "sheesh" far more often, and this made me wonder if this interjection is regional. Do you use sheesh or yeesh or both, or something a little more spicy to express your irritation?