I'd been doing a lot of research into this before buying. My major requirements were: a) Retention on power off b) multiple loops My intentions are to use it: a) with my main band, to trigger drum loops and some synth parts we added in the studio. b) with my rock/jazz/funk/trance side-band for live looping of grooves so I can play some keys or percussion at the same time. For the money, the Boss looked like the best option. I knew going in that it doesn't do stereo sound and that the record then immediately overdub is tricky to do. But I don't see me doing that much layering, although that might change over time. So, I've only had limited home use so far but I'm very impressed. The sound quality is great, the storage capacity (5 minutes +) is excellent, and the loop tempo quantizing is a godsend. You can tap out your tempo and set your time sig. Then when you record, at the end of your recording it'll basically make sure that your loop has that number of beats in the last bar. So if you stop recording a hair too early when using it live, all is not lost. I haven't tried recording anything with mixed time sigs yet, I'm sure for that I'll have to basically say that each bar has one beat to avoid the quantizing adding some extra empty beats I don't need. Anyway, that's my report so far. I probably won't be using it live for another month or so. But so far so good. I've heard great things about the L6 DL-4 as well, but I don't think I've heard from anyone who's used both.