Forgot to add - the Herdsman Lake area is best if you want to walk around the lake and see a bit of nature each day. Otherwise, the 'better' area could be considered up on Cambridge St and nearby. That gives you much better access to the cafes and shops, if that is what you are interested in. But, you will probably pay more! Newer developments always happening too.
I have a cousin that lives in Wembley and his flat near the lake is pretty basic, but cheap rent. Never had any problems that I know of. There are heaps of units on Herdsman Parade and it really depends on what you want to pay and what you want. Some are bigger unit blocks and other are smaller and in better streets coming off the main one. The bigger blocks have lots of different types living there, so there is more chance of having a problem neighbour I guess. Moondine Drive is supposed to be pretty good, but you really need to drive round a few times and check out the better looking places to see for yourself.