You should be good on anything up to about 10 lbs, and the size of a 10 lb pork butt. You will not fit a larger turkey in the Jr. I brine my turkeys in a cooler, surrounded by ice bags. Same for large briskets. My Jr. is used for pork loins, butts, tenderloins, ribs, beef/deer jerky, chickens (whole & parts), etc... Briskets and whole turkeys get a bath in the cooler. The full-size Briner will accept a whole turkey, but I don't have the real estate in the fridge for it.
I'd like to have another Jr., but not sure I'd ever need 4 of them. Great price, though!