I have the iso's that i've created from playing around with it. If you hope on AIM, i can transfer one to you.
Winpe is definitely not as easy as using bartpe as Bart has definitely put a lot of effort into the whole plugin support and making his product as easy to use as possible.
Basically, winpe is a stripped down version of Windows with only the bare components. The cd image boots to a floating cmd prompt window in a blank desktop. No icons, no taskbar, nothing, just the floating cmd prompt window. And you enter commands to load up normal apps like notepad, regedit, taskmgr, etc. Things that aren't included by default can easily be added
This is pretty bare bones, but it does have some nifty features that Bart might not. Because it is Vista-based, it have ip4 and ip6 support. It "supports driver injection, which enables you to load drivers either before or after Windows PE has launched". If "you start Windows PE and discover that it lacks a necessary driver, you can load the nonstandard driver from removable media and immediately use the hardware without rebooting." Useful when building the cd for the first time and trying to get everything to work right.
The only bad thing is the vista-based winpe 2.x needs 256mb of memory. You'll easily know why when you start looking at the source .wim file and it is 160MB all by itself and that it, by default, wants to create a virtual 32mb ramdisk as well. I tweaked my test virtupc machine to only have 128mb of ram and it errored-out when trying to boot winpe. "Ramdisk device creation failed due to insufficient memory."
Since the cmd prompt window that gets launched is essentially a type of autoexec.bat script, you can edit the script and make it load anything you want at boot. Write your own custom UI and have it launch. I haven't played with it yet, but supposed I can inject MHT support which would enable me to create a web-based application using only html code. If you've never used .mht files in the past, they are pretty powerful and would enable you to create a simple UI to launch apps. At least, from the documentation i've read, this should be supported, i haven't tried injecing the support yet. I can try it tonight.
Good article to see what it looks like and instructions on how to download and create a basic image.
http://mattoid.com/data/computing/winpe_and_imagex.htm