Oh this is great.. I think 90 days of Free trial is enough and I am sure the users would get happy and satisfied on that.
One caution for the technet enterprise trial ... "After the 90-day Trial expires, if you wish to continue to use Windows 7 Enterprise, please note that you will be required to purchase and perform a clean installation of Windows 7, including drivers and applications. Please keep this in mind; Windows 7 Enterprise is not available through retail channels." Installing everything from scratch is a lot of work; I appreciate they are being up front about it though.
I think using Windows Vista Business OEM better with Windows 7 Enterprise RTM I have buy laptop Dell Latitude E6400 and get DVD Windows Vista Business OEM , i using it in 1 year and run it good