I have had both in the same room.... 8200 cu ft...
How large is your room...? I'm estimating 4600^3 with a search I found 24x16 cathedral ceiling....
The Plus/2 would do very well in your room, better then a Single PB12-Plus, otherwise I would say 2 PB12-Plus's would work better...
In a room that size, dual subs would be much better at smoothing out FR.... I started out with a single Plus/2 and then added a Plus, and it worked out fantastically, but when they announced they were dropping the Plus/2 from their lineup, I snatched up a second. Dual Plus/2's annihilate my huge room. I moved my Plus to my bedroom setup, but eventually replaced/sold it for a JL Audio F112 for improved SQ in that small room, but the LF is less with a sealed sub compared to the ported.
Do you have room for dual subs in your room....?