You should start with your own investment goals, then conduct market research and decide on the market that may best meet your needs, then look at listings, once you locate properties, get a rent survey and run a investment analysis using the APOD form (Annual Property Operating Data / free / google it).   

Is that data recorded somewhere other than with the broker? 

Also, limit the  opportunity where someone can can fill in data in areas like Other Contingencies or Other Considerations.  

I've met a lot of investors combined with the information here in BP that helped me out tremendously.  

You can find good data on REALTOR.com as the feed is direct from the MLS.  

It doesn't look like you are running into any issue at this point but an input page would allow you to control your assumptions better and give you additional ways to enter data.

I haven't met a 'great' realtor yet, and figure s/he would probably snap up good deals.

Once I have all of those put together it is very easy to see if the deal makes sense.Once I have all this data I can pretty much see a worst case scenario and a best case scenario.

Historically, appreciation has just matched inflation (see the inflation adjusted long term Case Shiller data).

They supply comps using SFR criteria and that's not how MFUs are evaluated.MFU 5+ comps show GSI, (NOI sometimes), cost per unit, Cash on Cash and Cap rate.Little secret for your research efforts: ASK for everything, but GIVE nothing and then listen / read the data.