Currently, we have created a reservation system using outlook rooms. Each test environment within the lab has a "room" that someone can book in outlook and gives the user/tester the ability to see what labs are available. However, there are limits to the amount of information that can be supplied for each "room" and it really is not easy to see further details of the "room" (server image, server os, sql server version, application versions, etc).
I know about LabAgenda, and may pursue this. But is there any other systems out there that people prefere?