We use Home Again because that's what our vet recommends. We may be insane for paying the annual fee, but have done so. It's an $18 piece of mind that we can alert area vets if a dog goes missing while we are traveling and not familiar with the area. Or, God forbid, we are in an accident and dogs escape the truck. I've had a cat disappear and utilizing the lost pet functionality on Home Again was the easiest way to alert vets to be in the lookout if a client brought in a "new pet" that looked like my cat.
We have also found two animals, without collars, but who appeared domesticated and took them to our vet to determine if they were chipped. The vet runs the scanner, determines the animal is chipped, calls a hotline to get contact info for "last known owner". In the dog's case a man was reunited with his dog who had run off while visiting friends near my home. The cat we found was chipped, but the phone number and email address of the owner in the database were no longer valid. The cat was probably left when a person moved out of an apartment- abandoned kitty is now our kennel mouser since we could not contact the owner on record and no vet info was recorded.
That experience said to me- no matter if you pay an annual fee or not, ensure your contact info is up to date.
I just saw Carol's thread asking about microchips, and I thought it might help her to see this thread so I am giving it a bump for her, but also because I want to report that I am disappointed in pettrac/avid.
The Pettrac/avid registry requires you to snail mail something to them to get the changes made. I just looked and they have not updated my dog's info yet. It's been over two weeks!
First microchps are branded. Most scanners ten years ago only pick up their chip. Avid is number one. They also furnish most animal sheltals scanners that can read not only there's but most of them. Dr.Stoddard out of norco. CA started avid. You should contact your local animal shelter and see which microchips they use. That way when they recover your dog it can be read. Most of the avid chips the animal control officer can check right from truck and take the dog right home. The chip from pet again they have to go to office and track it down mostly by calling as some has already experienced It wasn't In system.