My usual post in these threads: Find a service in your area before you need it.

I called a service in my area and was told they usually cannot do "same day" appointments. This made them unsuitable for my pets since they each needed immediate care. Also, they tend to be a bit more expensive so that may be a factor.

I've used the same vet for over a decade so all my pups are relatively familiar with the location and practice, which helped immensely when the time came.