Where is the strongest rental market in Metro Detroit?

[Martin S.]

Hello everyone, this is an amazing site, I learned a ton here and I hope you can help me with my dilemma today... 

My dad will be moving to SE Michigan (Metro Detroit). He wants to buy a duplex so he can live in one unit and rent the other. We are looking for the strongest rental market in Metro Detroit.  I have a couple great rental properties in midtown Detroit and I know the market there really well.  But I'm much less familiar with suburban Detroit rental market. My dad, who has helped me renovate all the properties, is looking for a safe but affordable town where he can keep all his power tools in a garage and not be too concerned about someone stealing them.  Detroit is not safe enough and Ann Arbor is too expensive so we are looking for something in between - Livonia, Garden City, Belleville, Ferndale, Royal Oak, Madison Heights, Superior Twp., Dearborn Heights, Berkley, Troy, Sterling Heights, etc.  Where should I be looking for a duplex that will be easy to rent and safe to live in? 

Any suggestions would be greatly appreciated.  

Marcin