Cloned animals that live to term are not inherently unhealthy or prone to disease:
Myths about Cloning | FDA.
More research as more animals are cloned may refute this current consensus. Similarly, as more animals are cloned, the technique will likely improve. I am not saying there are not considerable societal,environmental and ethical questions, but Planet of the Apes aside, there are considerable potential benefits in terms of companion animals, endangered species preservation and recovery of extinct organisms.
Edited a typo.
