Which model, they're very different? I've had many.
The B Bass 6 is a gorgeous instrument, tiny, light and well proportioned for a 6, with a thru neck of varying wood quality. Some basses are quite plain, others wouldn't look out of line in a row of Foderas.
They're well made, play great with a nice thin neck. The only slight issue is that the bridge isn't quite woman enough for all those strings so it curls up 1/2 a mm or so at the ball end. But they still hold their tune and it doesn't usually get worse.
The B Bass 5 is a rather different shape and generally not as nice or well made as the 6 in my experience, but YMMV.
The B Bass 4 is like the 5 but rather nicer. Pretty and light, it's a great bass with lovely tone, in my experience let down by the weird drop D bridge lever which I never quite got sorted, but it was a 'rescue bass'.
For the money you're getting a lot of bass whichever model. I wouldn't pay more than £250. Good luck finding spares!!
Coupla sample vids, 4 and 6 https://www.youtube.com/watch?v=4Juo-y0craU and https://www.youtube.com/watch?v=3T3YD9t45HA