I'm not an expert but I do have a year old Yorkie and a four year old female maltese........love them both.
But I would add another maltese in a heart beat! Wouldn't even have to ask my husband about it.........he loves the maltese breed because of their sweetness and believe me she is 100% of hairy sweetness. The eye staining can be the result of lack of knowledge as to the cause and then making the necessary corrections. We got the maltese at 2 yrs. old and her face was so nasty looking we hesitated to get her.........so glad we didnt let that stop us.
She is a beauty. I most likely would not get another yorkie (and I love my Toby) because they are alot of terrier action. The maltese is more layed back to me. At least this is the case with my two kidos.