I know this is a very old thread, but it comes up so high in SERPs, even now, and it is still an important subject, especially to those of us who are now embracing open source platforms to run our real estate businesses, so I thought I would chime in anyway:
As a real estate broker with a Joomla 1.5 website myself, and who has looked at many vendors and their solutions, as well as having dozens of conversations on the subject with other agents and vendors, I can say that you will never ever find any one "magic bullet" plug-in for handling real estate IDX, for Joomla or WordPress or Drupal any other CMS.
The fact is that every real estate market is different, and IDX is NOT, as many may think or would like, a "standard". No MLS's IDX data is going to conform to any common standard as to what it contains or how it is formatted. The only commonality (generally) is that the IDX data would first need to be downloaded from the MLS with appropriate cron jobs, ftp logins and passwords to the vendor's or brokers server, or accessed dynamically via the newer RETS access technologies, if the MLS supports that. Once the downloaded data is on the broker or agent's website, it will then require significant re-formatting, including complex data normalization and database up-loading, via off-line batch processing or custom php or other programming. Those processes will be totally dependent on the particular MLS's IDX unique data formatting and contents. Then, every time the MLS decides to change the IDX data feed in any way, those processes will probably break and need to be re-programmed. Unless a vendor has already developed these processes for a particular MLS, and maintains them on their own servers, in close coordination with each MLS, any solution would only be temporary. Finally, given the complexity of these processes and lack of standards, the skill sets required to keep everything running smoothly will not be within the grasp of most real estate agents.
Therefore, no one standard plug-in will ever exist to do everything that is required.
Some vendors seem to have developed plug-ins to handle IDX data that has already been successfully imported into their own proprietary database designs, so their components will then understand it, and the website owner can then customize the display of the data as they see fit. But even that can be very risky for the agent, as all MLSs have strict standards about how their IDX data is displayed, and no one vendor or product can be held responsible for doing that as the MLSs may specify. It will also always involve significant compromises, as the vendor's database design will generally be a "common denominator" subset, consisting of data elements that are common to nearly every MLS. That means they will probably require significant customizations to handle a particular field that may be deemed critical to some parts of the country.
The only viable solutions I have found involve IDX vendors that download and maintain the IDX data on their own servers, and then provide components and/or interfaces to that data from open source platforms like Joomla, WordPress and others. In most cases, these vendors will provide access via IFraming, which does nothing to improve SEO for the real estate agent's website, but is very easy to implement and maintain. A few vendors have successfully integrated IDX data (still on their servers) with a client's website (usually also on the vendor's servers), usually via RPC calls, sub-domains or other techniques, where the IDX data appears to the search engines to be on the client's domain. Those solutions provide the most SEO benefit and flexibility, but are typically more technically challenging for a real estate webmaster to implement.
There are always exceptions to the rule, and some real estate brokers and agents, probably at significant expense, have been able to successfully get their particular MLS's data downloaded to their own servers and displayed on their open source websites. But those successes are few and far between, and I am sure that they will typically not be agreeable to sharing their successes and technologies with other local competitors in their markets.
Ron Goodman, Owner/Managing Broker
Denver Home Value Realty LLC
Denver, CO, USA http://www.DenverHomeValue.com