I applaud your question and the work you're doing on behalf of the homeowners at Briar Chapel; unfortunately I don't believe you're going to find what you're looking for short of contacting the various communities in our area.
I'm very familiar with Briar Chapel having sold a number of homes/townhomes there. As Desiree points out it's very tough to do an apples to apples comparison as there are townhomes, condos, and single family properties within the development.
Having familiarity with a wide variety of subdivisions in the area, my general opinion is that Briar Chapel's fees are very reasonable for what is given. The maintenance of the roads, trails, parks, pool, gym clubhouse and sewer system etc. There aren't too many communities that offer as much bang for the buck in my opinion.
I'd love to know the final results of your comparison once your done and hope the HOA appreciates your efforts.
I think it is a great idea to do a comparison but there is no one source of data.
In doing a comparison you have many factors to consider. Communities may have similar amenities but the # of households will greatly affect the HOA fees. Also, comparing a new neighborhood to older neighborhoods poses difficulties. Older neighborhoods may need assessments to take care of long term maintenance issues. Pools always add additional costs because of insurance liability and maintenance.
Your neighborhood is mixed with single family and townhomes. This also requires different HOA fees.
Also, Briar Chapel Has a community septic system. Another cost.
Please feel free to contact me if you have any questions.