My buddy has the Primos Power Dog we've been running the past week. Nice unit, cost him $100, remote controlled, completely wireless. Works, does its job, but seems to lack a little volume from what I'd expect. With only 5 or so days of experience with it, it is hard to say how well it will hold up, but up to now it has been doing its job.
One to look at anyways. The Foxpro Spitfire has been getting a lot of good press lately, no experience with it so can't give you any info other then the name.
Good luck to you, I hope you cut a few Yotes.