>>Fair enough. Could you provide some sort of criteria or anecdote describing how you found your current dog sitter?
I'm spoiled and lucky. My breeders (who are also my friends) board our dogs when we need them boarded. It just happens that my breeder is the director of the breed organization for my region, and his wife is the director of the rescue organization for the same breed in my region.
They are basically what all the books/guides tell you what to look for in a good breeder. I'm not sure many people are fortunate to have that type of resource available to them.
I myself would be uncomfortable boarding a stranger's dogs, and that's counting the fact that both my wife and I have certifications in pet first aid. Not all dogs are alike, and things like how well a dog is going to integrate into a boarder's home with existing dog(s). Not all people are equipped to handle manifestations of aggression or dominance from a boarding dog towards other dogs and/or humans. Not all people are careful about what food they leave lying around within reach of a dog. Not all people are careful about how escape-proof their back yards are. Some of the people could use your unaltered dog for unethical breeding while you're gone. Lots of stuff can go wrong. You get the picture.
All I can say is that if you're really attached to your dog(s) like I am, then you should be very discriminating about who you choose to care for your dog. Finding a caregiver online is totally different from other types of services, and should require careful consideration. It's nothing at all like selling a good, meeting people or dating. You're leaving a live being in the hands of someone based on some relatively anonymous and not necessarily informed reviews.