The word mutt doesn't bother me, it just means mixed breed. And as long as someone isn't putting a dog down for being a mixed breed/mutt, then I have no problem with the word mutt being used.
Yorkie-Pom mixes sure are adorable (what dog isn't).
But I'd go to a local animal shelter and get one rather then pay a lot of money for one from a breeder. JMHO