Thanks for offering this question Al. The short answer is that 2-4 plexes are not performing well in this rental market in most areas.
The glut of single family home opportunities has softened the condo, apartment and multi-plex market considerably. Why rent an apartment style unit when you can get a home for the same money?
That said, I'd look in areas that have good job/economic support and less competition from bank-owned homes gone to the rental market. In a recent article I wrote on our investor's blog site, http://www.greatinvestmenthomesaz.com,
I interviewed several top property managers and asked what areas are the best and worst rental zones.
Every property manager interviewed advised staying away from the east valley. They found this region to be over-saturated and economically troubled. Most said the same of the west valley, especially south of I-10. The upper west valley, Peoria & Glendale, show some good prospects due to fine schools and job opportunities. Most everyone we interviewed felt good about the central Phoenix corridor from downtown to the 101.
We are big fans of the downtown area. We have a full article on this region at: http://www.greatinvestmenthomesaz.com/2009/04/investing-in-d
Take a look here to learn about the opportunities in this area.\
Again, I have to offer caution on 2-4 plex properties at this time. It is not that you won't/can't find a tenant, it is that it may take a while. I did a quick search on the MLS for rental properties. Let me say first that the MLS is not the best place to find a tenant so the figures I looked at simply offered trends. However, in the past 6 months two time as many single-family homes rented in compared to condos, townhouses, patio homes, and duplexes.
In conclusion, I'd stay away from the west and east valley as the competition to SFH is very high. There are about 125 duplexes & 4-plexes offered for under $200,000 on ARMLS today. If you can buy right, not get into too many expensive repairs (a problem with multi-plexes because the properties are generally pretty old) and get into an under $500.00 per unit price point you could have a winner.