I have been using ASPCA for my aging dog for about a year now. I did a lot of research to ensure my dog would be covered since many companies offer cover just very basic services. There are some companies that won't even cover dogs/cats past a certain age.
ASPCA has reimbursed me for dental cleanings, meds and various doctors visits.
The claim process is pretty simple and easy to follow. I've only had to follow up a couple times when they required additional information from the veterinarian. That held the process up for a couple weeks.
I'm glad I chose ASPCA, its been a good experience!