usually when people facing a failed exchange server or failed installation, admins/consultants were using the ADSIEDIT tool to remove the Exchange server object from active directory, people were using this article http://support.microsoft.com/kb/833396.
I have seen an internal discussion that shocked me, for years I was using this article to remove failed Exchange2010/2007 Servers from AD, I know that I can use the recover option but it was fast and easy to use ADSIEDIT and as long it is ok to use it.
The discussion was about how safe it is using ADSIEDIT to remove Exchange server object from AD, surprisingly the response was that it is not recommended for Exchange 2007/2010 to use that method, also the above KB only applies for Exchange 2003, and there is no documented way to manually remove Exchange 2007/2010 and the only way to do it is using the setup /m:recoverserver, Thus using ADSIEDIT is not recommended nor supported.
Microsoft recommends only using ADSIEDIT only as a last resort if nothing works.
I know that it was popular even on the forums to use ADSIEDIT, from now and on use it only if server recovery failed.