It is a good idea to invest if and this a big if you do your home work, can afford it, don't buy a property that is more than 30 to 40 min. away and are willing to handle renters. Although you can pay a manager anywhere from 8% to 15% depending on what you want them to do. The main thing to work out is what kind of cash flow are you able to get, will it be negative or positive, what is your investment strategy are you in it for cash flow or long term investment ? As far as driving rents lower I don't see that as a factor, the only thing I have seen as a factor is the basic unemployment rate, as the major lay offs occured in this area earlier things have stabled out a bit. One other thing you can look into is what rents are going for versus what you will pay in mortgage and up keep.
I hope this helps, as always feel free to contact me with any questions.