Hi! I have a Yorkie and then 16 months later got a Maltese puppy. Both of my babies are large....Phoebi is 12 lbs. and Chan is a "wee" bit over that...lol!
First off, I wouldn't consider 5 years old to be an "old" dog in a small breed. Their life span is well above 10 years.
As far as an adult dog versus puppy, I would say that would just be your personal preference. Potty training vs. potty trained....leash trained vs. non leash trained.
If it were me, I'd spend some time with the Maltese that your neighbor is looking to rehome. Maybe even a home visit with you? I don't think that's an unreasonable thing to ask of your neighbor before making a final decision.
Oh, one last thing. Maltese "tend" to be much more subdued than Yorkies. They make a wonderful companion for each other.
Good Luck to you!
__________________ Kim  Phoebi Chandler |