I have my sights and heart on the 4b2b for 550k (I can probably get it for a less due to it's condition and needed reno ), the house is in poor shape, the resident is a stage 10 CODE RED hoarder, but in the perfect neighborhood.

The central air conditioning is not working in my rental in Aurora, CO Thanks, -Darren

Condition of the roof?

I basically pulled comps and did my own appraisal based on rents and conditions of the buildings...they had them assessed in some cases 30 or 40K higher than what was realistic.  

In addition to asking if they paid rent on time, you want to ask if there were any difficulties during the lease and if they left the property in good condition.

I live in FL so I know about having to use A\C year round.As you know people mention a brand and price but not model which will ultimately determine the total cost.I was in the exact same situation and due to the rusted coil tubing, and overall condition of the Air Handler decided for a total A\C replacement.Payne is considered "Builders Grade" lowest grade and some A\C guys argue not to install them because it reflects on their reputation when you have problems with the system.Look for the highest seer rated, quietest, best warranty HVAC that is fairly priced.The installer is a HUGE part of the HVAC's life span, along with your regular changing filters, cleaning coils when needed, cleaning drain lines and vacuuming dust out of the Air Handler Cabinet.

They have put some conditions on the purchase.

The house is in very good condition, other than it has no central heat and air and some countertops and laminate in the kitchen.

Be sure to note in the move-in property condition report all items that are not attached to the building which you are leaving for the tenant's use.

The broker tends to be more in tune with what is transacting and market conditions.