well. I have three commercial buildings now . one is for my own business. the other two for rent .one has 4 units.dostair is a chinese restaurant signed lease for 10 years.3 units are month to month but are all good long tenant.bought at $450.000 in 2004 .rent $4100 per month.but tax is up to $8000 per year .insurane $7700. maintance fee $2400.per year. another one just bought in sept.2008 .$325.000 rent $4000 per month . insurance $3300. tax $7000.per year. so far so good .now only one vacant.loosing $700 per month. as my opinion.for commercial investment 1. good location .better in downtown or good traffic .2. units are not so big in case vacant you wont loose so much. 3 find good tenant better with lease and good business. ... most important is LOCATION