I have VPI pet insurance to cover both my furbabies. I've submitted in past several claims to VPI and they have been pretty good in covering the expenses (more ~50%). I've also had ASPCA before and I didn't really like them, b/c it took them forever to process a claim and most of the claims I've submitted was not reimbursable.
If your pet is covered by VPI and they develop a medical condition later on, they will continue to cover the medical condition. However, if your furbaby has a pre-existing condition and you sign-up for VPI, they will not cover it. In any case, here's another thread that may have more info -
http://www.yorkietalk.com/forums/yor...insurance.html