Build a duplex or 4plex

[Mike Spero]

i just purchased a lot that i would like to put a duplex or 4plex on, so i can have some income for when i retire. In the area are large multifamily properties, with pools and clubhouse, etc. A 600 sq ft 1 bedroom is going for $700 per month, my 4plex would be the same, why would someone want to live in my 4plex, when they can get more at the other place, can i compete with them? Is this a good idea?