Took them on a few trips about 15 years ago. I think there had been a decent jump in the range around that time. They worked but for Algonquin tripping they weren't useful enough to become a normal part of the gear. I think part of that was that folks didn't keep them on all the time because of the battery life.
On the other hand on an extended river trip outside of Algonquin last year, they were used daily between the 3 guide boats in our group of 7 canoes.