I have a couple and I don't have any complaints about them. Turn'em on and the beep and they don't eat batteries. I've seen threads go on for pages discusssing the best beeper collar. It's not a major purchase nor one of life's great decisions to me.

However, If I bought again or were starting out, I'd get a two-dog combo beeper/training collar with a remote. More money, but a lot more versatile.