In the past week I have been in my "lab" testing out WDS, AIK, SIM, and the included tools. Everything has gone quite well and the documentation has been good especially for SIM. WDS is really pretty simple to use and I like that Mixed Mode is available if you would like to retain RIS images. I'm just getting in to adding drivers to images and other more complex operations.
I ran in to a strange issue where I could not delete files from a mounted image while using explorer. The issue does not exist when I delete from the command line. Turns out this is well known and was blogged by one of our testers over a year ago. It is due to Explorer moving files to the recycle bin rather than actually using the "delete" action. According to the post the wimfltr does not support the "move" action. Good to know!