In my opinion the best collars are the Quick Trak-but the best overall reciever is put out by Wildlife Materials. They have a few different recievers that can pick up from 3 dogs to 400. I have the TRX 1000 that will hold up to 200 collars, which is good for someone who has a lot of dogs & comes in great for helping a buddy out with his. I think all the collars work with most recievers as long as it's the right frequency. I also have a Johnson RB 10 which will hold 24 collars & picks up almost as good as the Wildlife. I might be willing to part with the Johnson system for about $700 (box & 4 collars). I have a friend who might be getting it but if he can't come up with the $$ then he'll just have to get over it.