I made this without the onion/pepper (personal taste), and I just used the cheapest cut of pork I could find (I think shoulder), and it was amazing! The leftovers are to die for as well! The only annoying part is pulling apart the meat (but it's SO worth it)!
I actually used pork loin because it is what I had. I did leave out the red hot sauce as my little ones have a tender palette. We really liked it. I used Sweet Baby Rays Vidalia Onion BBQ sauce. I thought the bbq sauce might overpower the root beer and Old Bay but it didn't. I have eaten the leftovers for days, I won't share them with anyone else. Yum.