I am remembering some of the research I did on the Omni 20 before I pulled the trigger. IIRC, the reviews were not very good, but the problem was that the wireless system for interconnecting several was hit or miss and that is how this item is market (I assume a Sonus alternative). I believe all review were favorable regarding sound quality.
Also at $80 (and if you have any use for an extra) you might get two and see of you can get them working either in stereo or as dual mono for better distribution of sound. If so that would be very nice! Don't get me wrong, a single does the job nice as you would expect, just thinking in terms of going from good to really good!