Thanks. I bolded the part where you said the SM goes where the BB goes. I guess I can't understand, then, why you would need both if loudness and tone were all one cared about in a cab. I understand the schlepping part, but are there any other advantages to one over the other if they both seem to be equal in other aspects ? For instance, would a 5 string player favor the BB over the SM ? I'm thinking more or less stand alone solution here, and not pairing up two cabs.
It's hard to beat the BB2 for a single cab, stand-alone solution, IMO. But, I don't have a SM yet so I can't say... I know the SM fans here might say the SM is the best one-cab solution. If all I cared about was loudness and tone, and I wanted just one ring to rule them all, and didn't have either yet, I'd very likely go with a BB2 rather than a SM (but ask me again in a month, after I've tried the SM).
Again speaking without hands-on experience with the SM yet, a 5-string player not concerned about cabinet size or schlepping might favor the BB2. I'll reserve judgement on SM until later, and in reality I am sure the SM can handle the lows of a 5-string much more than adequately, because it has the same 12" driver as the BB2, but the BB2 has some super low-end warmth, it can fill a room and make it seem like you have PA support when you don't, in the low end.That's the larger box talking.
As far as the BB2 and SM being "equal in other aspects", my understanding of the SM based on user feedback is that the SM might not go quite as loud (but close and I don't max out volume in my playing situations), and doesn't have quite the extreme depth of bass (due to smaller box); but the BB2, honestly, has more low end that you'll need, so a little less than almost too much (though it is NOT "too much," is there really such a thing, lol) can't be bad, and surely has plenty of lows compared to any other cab than the BB2, which just has more than any cab I've ever heard.
So, bottom line-- and this is mostly personal preference-- if I were starting from scratch and buying one only, I'd probably go BB2 (which is, in fact, the first BF cab I bought). But versatility in gear options is important to me, so in my case, for the 2nd cab I want to have a SM rather than a 2nd BB2, for the reasons given my previous post-- another, smaller-than BB2 but more-powerful-than-One10 option, and to pair with the BB2 for killin' it with overkill.
Since I haven't played through or heard a SM yet, you should take these opinions with a grain of salt.