100% Awesome Sauce!
I've been a Sheldonista for over a year. Of course, I was attracted by Oso the pug (and yes, Dave Kellett does own a pug). My Batpug avatar is from the cover of one of his books (I have other Sheldon avatars at livejournal).
Some of the things I love about this strip... Oso (natch), Flaco (the lizard who thinks Arthur the Duck is his father), Arthur the talking duck, and Gramps. I love the sense of humor. I love the little jokes that you know that only a science fiction/fantasy/nerd is going to get.
Occasionally Sheldon also takes little pot-shots at comics too. A few weeks ago there were a few Aquaman strips. Arthur occasionally dresses up as "The Duck" (a la Batman).
I subscribe to Sheldon and make sure I read it every day (and squee every time that Oso shows up).