I've not heard the PB13 but I did hear the PC13 Ultra and liked it. I chose the EP800 over SVS though for very much the same reasons Jay and Dan have mentioned.
The EP800 goes lower than the SVS, and for my HT application that was important. The reports of the EP800 blending better for music also factored in, though I did not test the SVS with music so I have no firsthand comparison. I will say the EP800 is outstanding with music, so I feel like I've got the whole package, so to speak.
Additionally, I needed to keep the sub footprint as small as possible and that is another area where the EP800 has an advantage over the PB13. The EP800 is also DSP controlled, which was another big plus in my book. Finally, as far as cost goes, the shipped to my door cost for the EP800 was only $130 more than the PC13 Ultra, and in my mind well worth it considering all of the advantages I get with it over the SVS.
For many people, though, and especially those in the U.S., the SVS will be a better bargain, and by all accounts they do make great subs so you should be happy either way
