Environment Overview:
Requirement: We want to generate the below reports
thoughts?
Not sure about GAC, but Quest Deployment Advisor was build (amongst other things) to compare 12 hive folders across servers. It is still in closed beta, but you could ask Quest for a release date. Also theres a webcast tomorrow (March 11th) on Deployment Advisor (and SharePoint deployment in general by Joel Olesen and Mike Watson).
What specifically in 12 hive are you interested in monitoring?
There are some other tools, including STSADM commands that can warn you if artifacts are missing on one WFE.
STSADM -o PreUpgradeCheck is part of SharePoint 2007 if you run SP2 and can be used for more than just checking if you are ready to upgrade to SP2010. It does not touch your data bases at all, and can be run on both a single server and a whole farm. Theres two obvious benefits of this: running it locally will only stress a single WFE server, which is good if run on a production environment. Also you can run PreUpgradeCheck on individual WFE and afterwards compare the reports against each other to spot inconcistencies across the frontend servers. Pre-Upgrade check on TechNet: http://technet.microsoft.com/en-us/library/dd793607.aspx
WssAnalyzeFeatures. This tool verifies if the feature definition files for all installed features are available on the file system, if the features used on a site collection are installed on the server (download from MSDN Code here http://code.msdn.microsoft.com/WssAnalyzeFeatures).
Bamboo SharePoint Analyzer can help you get an overview of your farm topology, installed patches on servers, solutions and features deployed etc (available here http://community.bamboosolutions.com/media/p/7160.aspx)
SharePoint Feature Administration and Clean Up Tool can help locating faulty features in your farm (available from Codeplex http://featureadmin.codeplex.com)
SPDiag version 2 is good for farm insight such as AAM’s or finding deployed solutions using the SnapShot tool. Diagnostics tool is also handy for detecting any discrepancies regarding best practices on configuration of the farm (Part of SharePoint administration Toolkit 4.0 that can be downloaded here http://technet.microsoft.com/en-us/library/cc508987.aspx).
Since they are both just a set of directories on the Windows Server Filesystem you can use any directory comparison tool.
Here is a list of tools http://en.wikipedia.org/wiki/Comparison_of_file_comparison_tools
I can only vouche for BeyondCompare.