Hi @Omer Bar,
On the surface your message above has two questions - what neighborhoods? and what metrics?
If you dig deeper though, its tough to answer those without knowing a lot more information. Are you looking for appreciation/cash flow/etc? Are you local and do you plan on managing the properties yourself? Are you looking for distressed properties that need rehab or more of a turnkey opportunity?
I think understanding a bit more about your goals would help many of the smart people here offer some sound advice.
One thing I will say however is even understanding a neighborhood in Milwaukee is sometimes not enough. In some areas (and maybe especially in the price range you're looking at) there are good and bad parts even within the same neighborhood. I recently bought a duplex I thought was a good deal, but I would not have bought the same house 2-3 blocks away. In my experience, its best to go there in person or have someone you REALLY trust go there for you. Ask yourself the question "will the kinds of renters I'm looking for pay the price I'm asking in this location?".