So I got this mute because I wanted a practice mute with amplified feedback.
My partner has the Yamaha Silentbrass (SB7-X, the latest version) so I thought I'd be different and buy the e-Brass for myself instead...
What attracted me to this is that it doesn't require the additional box of electronics that the Silentbrass does - just plug in headphones and go.
There are upsides and downsides to this...
The BestBrass is heavier than the Yamaha in the bell (because it's mute plus electronics rather than just mute), but you don't have a mess of cables everywhere like you do with the Yamaha.
Soundwise, the tone is usable for practice purposes - it comes across well enough to diagnose any issues and loud enough that you don't end up overblowing the mute (the biggest problem with practicing with a very quiet mute in)... the Yamaha might have a slight edge in sound quality, but as it's a practice tool and nothing more this doesn't really bother me much.
As the other important aspect of practice mutes is that they're quiet (for the people around you, or next door or whatever), maybe I ought to say something about volume - yes, it's very quiet and it'll do the job of keeping fussy people around you happy.