I really liked my Boss ODB-3, but I found that with it on, I'd have to turn the highs up a lot to get over my guitarist. I had to turn the highs up in order to even tell that my signal was being distorted, and then it became a little harsh sounding on my lower end amp. I played it through my girlfriend's Mesa 400+ and it sounded a little better, and not as harsh, but still had trouble in the mix.
I have a very midsy tone, and basically obliterate my guitarist normally, but I was having trouble cutting with the Boss. So I sold it, and bought a Guv'nor 2 on eBay, should be recieving it soon. Hopefully that will be better.