I have found the Shorts to be better for me over the Boli. I find the boli to be a little harsh and not as flavorful. I like the Boli PC a little better but that may be just me and the 5er I had may not be from a good box. But I liked the shorts enough to get a 50 cab.
Thats a tough choice as they are my top 2 favorite short cigars. You need to have a box of each. But if you can only afford 1 right now. I'd go with the Boli CJ's. They have been very consistant over the years.
I'd take the Bolivar ... i've never smoked a Bolivar CJ but I have smoked a Party Short and found it to be woody and peppery and not much else. I know that folks LOVE Party Shorts but they're just not my kind of stick.
Probably not the kind of helpful reply you were hoping for.
Shorts. I like the Boli CJs as well, but if I was making a list of cigars never to be out of, Shorts would be on the list, but Boli CJs wouldn't unless it was a very long list (as Greg noted, Reyes would definitely make the list).