I used the 350 combo with my church band this past Sunday using my fretless Bee (in the avatar).
The first question is whether or not it was enough. Yes. @campbems I think you would find it more than enough for smaller churches. I know the woofer is not the same as the BA210V2-3, but my gut says it still may give you some of the characteristics you like in the 210 vs. the single 12. You will lose the dirty channel on the head but everything else seems much the same to me including the quickness of the attack.
We play at a moderate volume but there was more than enough. Indeed I started out with the gain and the volume controls both at about 11:00 and the EQ all flat with the contour fully counter clockwise and the sound person told me I need to turn down a bit. FWIW, I generally do not put the bass through the FOH. It is a small room (seats 120) with excellent acoustics. Putting the bass through FOH would basically mean removing my speaker cab from the equation. The rest of the instrumentation is drums, acoustic guitar, synth, and acoustic piano.
My first impressions are that the cab has a good deal less bottom end than the BA12-3 which makes it sound a bit more focused on the mids and a bit brighter. Not quite honky or boxy but leaning in that direction. It sat very nicely in the mix though. Bringing the bass up a tiny bit and the trebles down or engaging the contour B a bit took it closer to what I like to hear.
Today I had a few minutes to play with both the BA10-2 and the BA12-3 using the 350 head and my fretted Sire V7. No surprises. The BA12-3 does have more bottom end, is a bit louder, and is more round sounding. The BA10-2 is brighter and perhaps a bit more punchy. Like the BA 12-3, it sounds much bigger, deeper, louder than it looks. The two cabs seem to play together quite nicely although the sound of the BA12-3 dominates. Playing the two together does seem to me to be more than the sum of the parts. There seemed to be more of everything including the increased dispersion that one gets from the array. I expect the magic isn’t the same as having two BA12’s but it seems to still be there to a lesser degree. Playing the cabs together with the volume about 12:00 on the 350 head and everything else set as above was impressively loud.
So, conclusions... The 350 head is likely all the power I need for any of my uses. Since I already have the 800 head as well, I’ll likely keep it but if I were buying it today, I’d just get the 350. One of these days I may decide to sell the 800 and get a second 350... or maybe not. It is nice to have the extra power even if I never need it. The combo with the single BA10-2 likely also covers almost all and perhaps all of my current uses. I prefer the overall sound of the BA12-3 to the BA10-2. While the BA12 is certainly not a large footprint or overly heavy, I do have settings where the smaller footprint and easier schlepability are real pluses. So... a trade off. We’ll see over time how I feel about that. Saying that, I am sure there would be folk who would prefer the sound of the BA10 over the 12. Different strokes. For them, the small cab is a huge win win. For me, it is a small question. All in all, it is an amazing little piece of gear.