Rel Strata III versus Rel Britannia B3

Hi all,

I am looking to match a pair of Spendor S5e's (powered with Simaudio I5.3) with a subwoofer and was trying to figure out if anyone has experience with the Strata III and its new "replacement" the Britannia B3. I believe that the B3 is a ported design from a structural perspective versus non-ported for the strata. (sidenote: I have heard good things about the B1 comparable or even better to the Storm in the ST series).

Anyone have any experience out there with both?

Thanks!