I am still in the process of evaluating VQMS. Previously I tried out VMWare LabManager 2.5. One of the biggest differences I am noticing is that VMWare had a very easy path to import an existing virtual machine into the system, and once imported, it was also easy to manage updates and changes to the image as part of the image library. So far I have not been able to import any existing images from ESX Server into VQMS. Trying to manually copy the image files into the VQMS library share has been one roadblock after another. First I run up against the 2GB file size limit when I mount the windows share using SMB, so my large 25GB vmdk files can't be copied directly to the windows VQMS server. To get around that I tarballed them, which made the file less than 1 GB. Now I can't seem to unzip my tarball file successfully on windows. I guess the file got corrupted somehow. It takes so long to try different steps I really am not getting very much accomplished.
I was able to deploy using empty configurations with an ISO file of the Windows XP boot disk, but of course I had to go in through the VI client and attach the vmware SCSI boot floppy to make it boot correctly and see the disk. Not very convenient, and not something I would want to hand off to general users to try and emulate.
Another thing I find inconvenient is the concept of Server Configurations in VQMS. You can only add a Server Configuration once to an Application Configuration. If you want a configuration with multiple machines that are based on the same image (with network customization of course) you have to add a Server Configuration for each one to the library in order to build an Application Configuration to deploy. In Vmware it was easy to take a stock image from the library and add it multiple times, with options to configure each instance as a unique machine (they used Altiris Sidgen to customize windows images). A recent project here wanted to build a test configuration with 50+ client machines accessing a server for a stress test. If I had to set that up in VQMS it would have taken all day. Assuming I was able to get the original client machine image imported, which I have not done yet.