i used a b4 and b2 for several years. they do reproduce low frequencies really well, and handle a lot of power. my stingray 5's low string never sounded so good! they are a very sterile cabs. they are loud, but lack "chest" thump, which i find really helpful on stage. it took me a while to realize that, in rock settings, i was blowing out the audience, while i was struggling to hear myself. it took a little bit of time to get use to adjusting the mid and hi frequencies with the attenuators on the rear of the cab.
i eventually moved onto something else because i grew tired of constantly changing the 1156 car bulb that they use as a fuse to protect the tweeter- you have to remove a speaker to access it. i blew two woofers while i had them, but they replaced them.
Andy, the main guy at acme, was really great with customer service! Quick to respond to emails, accepts phone calls, all business, very cordial.
if you are a bass straight to the amp player (no effects), &/or a slapper, these cabs are great. my taste simply changed.