What else is in your system, especially your pre amp? The 8008bb is fully balanced - it has twice the circuitry of the 8008st. If you don't have a fully balanced pre amp to use with it, you'll just insert the supplied jumpers & use the single ended (RCA) input jacks. It also has two power tranformers instead of the one in the 8008st. If you have hard to drive speakers, you might need/want the 8008bb.
I own a 4004MKII - the predecessor to the 8008 series, it has two transformers like the 8008bb, but has single ended inputs, like the 8008st. Thats fine with me, I'm using it in my video system where my processor/pre amp is single ended anyway.
Post the rest of your current/wish system, you'll get input from members who've lived with the components & intermatched them.
p.s. there is a camp that says you can't have too much power, & another camp that says don't make the system any bigger/more complicated than you have to..
This should start a debate...