It should come down to the tone that you like better. Unless you plan on using GK cabs (which is not a bad plan) forget about the Bi-amp for the moment. It's a cool feature but you can live without it, and I do. There's also probably not a huge difference in volume between the two. They're both stupidly loud. It may seem like we're being unhelpful but you will have to choose with your ears.
As B-String says too, there are a lot of cats who have had SVT7s go pop on them but that just means you need to be mindful of getting a reasonable warranty (extended if possible). To put things in perspective though, my GK has blown up on me twice while outside of warranty, so try not to let the whole reliability thing get the wind up you. Every basket has a dodgy apple or two.
Gallien Krueger Club #948 Spector Club #391