Outstanding quality and ease of use
I moved from analogue recording studios to computer-based recording fifteen years ago. Initially the digital domain was productive, but it seemed the more I upgraded my digital audio workstation, the less time I actually spent producing music. Latency issues, soundcard incompatibilities, the complexities of the software: a lot of things conspired to keep me focused on the technology rather than the music.
I bought a BR-1600 in the hope it would make me more productive. After only a couple of weeks of use, that is certainly true. There's a bit of a learning curve, but not as difficult as shifting between, say, ProTools and Reaper. The 380 page Owner's Manual is comprehensive, and there's a handy quick start guide. Plus there are a lot of resources on the internet, including the Songcrafters forum which has many Boss BR users who are happy to share their deep knowledge. The BR-1600 has its shortcomings, but no show-stoppers so far.
 It's quiet. Despite a Ghost case, my DAW would contribute its own background noise to the recording process. If you listen closely, the BR-1600's 80GB hard drive has a low level rumble, but it doesn't get tracked.
 It's efficient. Recording with the BR-1600 feels to me more like the analogue recording of yore. The model has dedicated buttons for marker and punch in/out functionality and, being digital, rewinding and advancing to markers is instant: it's the best of both worlds. I just hit record and focus on the music. Accidentally overwrite a good take? No problem: it has a great Undo function.
 The audio is high quality. Sure, it's "only" 16bit, but so are CDs. The internal DACs sound clean and flat. The finished product sparkles.
 It's packed with features. The guitar, bass and vocal effects are still best of breed, even though this model has been out of production now for several years. For mixdown there's reverb, chorus/delay, compression and EQ. My music mixes time signatures (often unusual time signatures at that) and the BR-1600 has made this easy once I learnt how. The drums sound great, too, and you can load additional kits from a CD.
 It's discrete. OK, this is perhaps not a feature that everyone values, but for years my workday computer has also been my DAW. My working day has the occasional quiet half hour when I could create a little music, but I've mostly passed on these opportunities because it's a hassle to shut down my work software, fire up the DAW, then restore the work environment when I've finished. The BR-1600 has everything I need ... in one separate box.
 No separate monitor mix. So far this hasn't been a big issue, but it would nice to be able to set up a separate mix.
 Exporting audio. The BR-1600 only has USB1.1, it only works with Windows or OSX, and song files then need to be transcoded. It's slow. The alternative route, writing to a CD, is probably better, but I've yet to find CDs that are compatible. Nonetheless, when you do get your tracks out and transcoded, it's easy to import them into the DAW of your choice if you wish to.
 Track solo. You can mute channels, but you can't solo. It's a shame this was left out, as I find it one of the most useful functions when you're recording. Still, it's not hard to mute all the other tracks.
Three issues are often mentioned in reviews that really aren't problematic for me.
The first is the green screen. I don't find it a problem to use; it's a little cryptic at times, but all the information I need is there. and it's easy enough on the eyes.
The second is the depth of the menu hierarchy, and the apparent difficulty of accessing the functions you need. My experience is that as I've climbed the inevitable learning curve I no longer even think about this: I know where to go and the key presses required take no time at all.
The third issue is the eight mono / four stereo configuration of the sixteen tracks. I don't see this as shortchanging users at all. In practice it's pretty much exactly the layout you need. I mostly record on the mono tracks, and do a sub-mix (all the guitars, for example) to a stereo pair, go back and repeat. Virtual tracks (16 per channel) mean you can retain all the original takes in case your submix needs tweaking later. For me, it's very logical and works well.
I highly recommend this machine. It's got me creating music again after several years of struggling to achieve any sort of output.