410 SP will go lower I think. It also might have more punch. If I had to pick one I'd get the SP. Lower weight, more compact, and it will baffle people when you tell them it's a 410!
Hopefully this thread won't turn into a battle about the loudness of isobaric cabs!
__________________
Jah bless de Reggae bassist--DR Strings Member #19
Flatwound Club Member #1993- GK Member #679
I appreciate the responses thus far. Any other thoughts? I hate to spend this much money and not being able to A/B these cabs, so I welcome everyones input.