Some lines are prone to terrible eye stain, be sure to look at the sire and dam and their eyes before deciding to get one.
Also ear issues can cause the tear staining. Sometimes antibiotics will help to clear up ear stains.
Maltese are the most laid back of the two breeds.
Yorkies in my experience tend to have more hyperness.
But thats why I love the Yorkies.
Maltese are very dear and sweet.
Grooming as long as you are consistent and don't let them go too long with out good grooming is not that bad.
There is wonderful products for white coats
Juzme
