DW and I are Trusted Housesitters and are currently on, I think, our 29th sit. This one's near Vail. Most of them have been in Europe, and it enabled us to stay in Europe months at a time, which we could never have afforded otherwise.
From the sitters' point of view, you get to stay in generally nice houses for free. You meet nice people, and nicer animals. Sometimes the hosts lend you their "dog car" to take Fifi to her favorite park or beach. One nice thing is that you get to go to places you'd never heard of, or at least never would have picked. Like Hastings, England for Guy Fawkes day and the annual re-enactment of the Battle of Hastings, which was not actually in Hastings but a 10-minute train ride to a town now called Battle. Their home is a 16th century building that had been an inn and was now a B&B.
From the pets' point of view, they get to stay home and continue their routines. For an older animal, this is no little thing. They eat the food they always eat, and don't get intestinal problems when the kennel staff gives the wrong food by mistake.
From the owners' point of view, they know their pets are getting close personal attention. We send photos or videos every other day or so. In Britain particularly, some folks have three dogs, and usually one is old, so kenneling them would cost 100 pounds a day. Their home remains occupied and emergencies are forestalled.
Trusted Housesitters offers background checks, but the best assurance is the reviews clients leave. After you have four or five, it gets easier to get assignments. I do think the price is a little high for the pet owner, especially if you expect to have your pet sat only once, but I buy a lot of stuff I think is overpriced, so maybe that's just the way I think. If you travel a lot, it's a deal, and if you live in an attractive town, you can usually get a sitter on short notice. For sitters, it's a deal, as it's only about the price of one night in a hotel.
DW is a photographer and we usually take and leave a bunch of digital photos when we're done. Sometimes we make dinner for the returning hosts. Sometimes they do that for us on arrival day. We have made many friends from doing this.
We usually have a video chat before the commitment, and sometimes during the sit. Hosts have their friends and neighbors pop in and introduce themselves sometimes. We've never had a bad experience, although sometimes the home isn't as clean as you'd wish.
It is true that some folks think "I'd never have strangers in my house!" and there's nothing wrong with that, either. Folks are different, and we embrace that.
You can ask me more questions here or by PM.