I've had my B2 for a couple of months now, and after a slightly laborious process of transferring my music from my hard drives to the B2 via USB stick (which I hasten to add isn't any fault of the unit or Brennan, I've just got sooooo much music!), I'm absolutely delighted with it.
Working from home at the moment as many of us are, I'm able to work my way through my collection on random and rediscover songs and albums that I haven't heard for years, handily assigning songs to various playlists as they come up so I've now got playlists for all occasions, some just my favourites by a single artist where there's an extensive catalogue, and others by mood or genre.
The web interface (particularly since I just downloaded the latest software version, which was a piece of cake using the remote to navigate the menu) is great, and the mobile app very handy for when the laptop has been put away for the day.
All in all, I couldn't be happier, and wish I'd done it ages ago (I ummed and ahhed over taking the plunge for about six months, and it was after reading so many of the threads on this forum that I was convinced that I should jump).
To conclude, if like I was you're deciding whether to invest the not inconsiderable sum for a B2, then I can say, hand on heart, that it'll be the best thing you'll ever do when it comes to rediscovering and falling in love with your music collection all over again!