Pros: Nice flavors, a bit different than your standard stout
Cons: It's not Guinness, but still a good choice nonetheless!
It would be rather unfair of me to compare Rogue Shakespeare Stout with Guinness, but I am afraid that I am going to have to, since they are both stouts, and pretty much representative of the brews from their categories (dry stout and oatmeal stout-Guinness being the dry stout). Please read on, intrepid searchers of e-truth, and see whether I am wrong in doing so...
Well, first off, I am more of a fan of Guinness in pint form freshly poured from the tap in a nice ambient pub. I have not yet had a Shakespeare Stout from the same arena, so I cannot comment on how this brew is from the tap. I CAN, however, compare and contrast the two in the bottled market, since I recently had one of each.
Guinness is a brew that is made to be savored and enjoyed, in my opinion. Rogue Shakespeare Stout is more of a "drink enough of me to get a nice inebriation going" sort of brew. Guinness is a bit more complex and a bit harder to get used to, while Shakespeare Stout is more of a "Jump in and like it or loathe it" sort of beer. Guinness is more heavy, while Shakespeare Stout is more of a middleweight in its class of beverages. Guinness is not so bubbly, while Shakespeare Stout is rather "American" in its effervescence. Also, Shakespeare Stout seems to have more of a "hoppy" flavor, while Guinness is more bitter and weighty.
I still prefer Guinness, but when I am denied that choice due to tap constraints or vendor availability, I shall gladly accept Shakespeare Stout as my stout of choice. I am not trying to put this brew down, merely making a personal choice to enjoy what I like more. I expect that not everyone will agree with me, but that is my e-pinion.
Footnote: thanks to Beerlover for pointing out that Guinness and Shakespeare Stout are different types of stout to me.