This amp has a great versatility thanks to its double preamps. One is a valve preamp, featuring a single ECC83 tube, and the other is a solid-state. You also have the "blend" feature so that you can mix the outputs of the preamps in any proportion you like. Then comes the 2-band primary EQ and the "Deep" and "Bright" switches which boosts the bass and the treble, respectively. If you need further fine tuning of your sound, you can use the 7-band graphic EQ.
I got three basses, a custom 6-string with active Duncan soapbars, a Rickenbacker 4003 and a '75 Jazz Bass clone old Hamer. They have totally different tonal characteristics but B150 can handle all of them with ease. I prefer 100% solid-state preamp for the 6-str to get modern tones. On the other end (100% valve), the Ric barks with its famous mid growl. With a 70%-30% valve/solid-state mix, I can get a typical Jazz Bass tone with the Hamer.
Additional features include dual inputs (active/passive), a soft-knee compressor (not a very pro one but quite useful), an effects loop, limiter and dual line outs (unbalanced and balanced with earth lift switch).
150W output is just the right balance for a semi-pro like me. Quite enough for home use but loud enough for a bar stage or a small-size concert.
Any cons? Of course. The damn thing weighs 39 kgs and is quite large so it is a torture to carry it around.