Are there alternatives to Sysinternals ADInsight?

There are known issues with ADInsight and it is no longer supported or developed. It has issues loading its DLL in certain environments, specifically on VMs (see http://forum.sysinternals.com/adinsight-doesnt-work-hangs_topic18891.html and http://forum.sysinternals.com/adinsight-operation_topic18963.html) (archive links)

The best solution I have found is to turn on Active Directory Diagnostic Logging as described at http://www.activedir.org/Articles/tabid/54/articleType/ArticleView/articleId/41/Default.aspx (archive link). Basically, you want to set the following registry values:

Path: HKLM\SYSTEM\CurrentControlSet\Services\NTDS\Diagnostics\15 Field Engineering
Type: DWORD
Value: 5

Path: HKLM\SYSTEM\CurrentControlSet\Services\NTDS\Parameters\Expensive Search Results Threshold
Type: DWORD
Value: 1

These changes do not require a reboot but are set per server, so implementing for an entire forest/domain would best be done via Group Policy Preferences. Once set you will find the resulting logs in the Directory Service event log on the DC. They are not exactly parse-friendly but can be wrangled with some regex. The best part is it requires no external utilities/code.

I would be remiss if I didn't mention that this level of logging may incur a performance penalty on a production DC. In my test environment, with only two DCs doing next to nothing, I see ~10-20 events/minute from just this setting.