Hi,
I just wanted to back up the previous posters on investing in the better class neighborhoods because of a few things I plan to apply for myself too - also veterans correct me if I'm wrong for any of these!
1) For buy and hold, it appears that one's goal will be to own more than just a few of these - so it seems like it would save yourself the headache of dealing with the more strenuous tenants/maintenance in the lower end properties vs. the higher end properties. Some people don't mind this, but generally speaking it just seems better to have more peace of mind when it comes to your day to day life and not putting up with things you can avoid!
2) Aforementioned - appreciation is one big factor that many people tend to take into account when investing in real estate - the lower end properties do not tend to hold much of an appreciation rate compared to their higher end counterparts (given the locations are ideal for both class of property). Not to mention more of your cash flow will be going right back into these rentals as a lot of the lower end rentals are older than the newer, more expensive properties, requiring more repair (also given the quality of tenant!)
3) Mortgage fixed rates are at an all-time low, so why not take advantage of getting the most of leveraging yourself with these cheaper loans? Also refinancing on properties in the 100k range versus the 50k range is more probable as well as less hassle to the banks - another headache saved.
It seems there are more reasons to invest in these types of properties over the older properties the more you read and search the forums on this type of topic - not to mention one basic aspect of investing is to stay within your comfort zone of risk - and based off of previous threads and experience from the more seasoned investors it appears there is less risk to invest in newer and/or better properties!