Hi there my personal view is that Midland isn't that bad a area. Yes you do still have the rougher parts, with regards to crime rates I wouldn't want to give the wrong info so if you click on this link you see the crime rates for all.
http://www.police.wa.gov.au/Aboutus/Statistics/Searchcrimestatistics/tabid/998/Default.aspx
there is several nice areas around Midland for example Boya, Gooseberry Hill, Kalamunda, John Forest, Jane Brook.
Thanks.