I bought these for using with the kids when we go on bike rides. One always ends up a long way ahead of the other, so now we take these with us. They are easy to use and pair, and we have not had any cross-talk with anyone else with similar handsets. I haven't tested them as far apart as 3 miles, but they definitely work well up to 1.5 miles.
They do eat batteries, so get rechargeables!