PA will neither improve or degrade in storage, provided you keep it tightly sealed. Burleys are fairly cellar-neutral in my experience. CH may improve a hair due to the VA component in it.Just for kicks, how well does Carter Hall and Prince Albert store if one were to load up on it?
None of these have toppings to worry about fade with. These are simple Burley heavy blends with a mild casing.
You can pop open a sealed tub of these OTCs from the 1960s or 1970s, and it will taste as if it were new. The older tubs are well sealed. The same cannot be said of the pouches.
I have no opinion on the later Middleton plastic tubs, as I have not had any around long enough to form one. I have six sealed tubs of PA left. So I guess will find out, as I am going to start smoking LLRR and some others more going forward.
As far as tastes, should you decide to stow some away, CH is a little sweeter than PA to me. Somewhere between PA and SWR to my tastes. But as I mentioned above, it is all like comparing different brands of cola. None of them are root beers, let alone ginger ales.