We have two condos and so far they have been great rentals. Like others have said just make sure you do your due diligence. I have kept in good communication with the property management company for the complex from the first phone call inquiring if they allow units to be rented. On the most recent one we bought the management company and neighbors told us they were happy to see us buy the unit because we fixed up the place, placed great tenants in there, follow all the HOA rules, and pay our dues on time.
I think it really just comes down to knowing your market and making sure the numbers make sense. I know my market very well and knew these complexes would be ideal areas to get into.
Also, I really liked the comment about FHA. For the units we currently have whenever we decide to sell it will mostly be to another investor or to first time home buyers so it is important that we buy in a complex that the buyer will be able to get financing.