Hello FrugalRain,
LANDESK's ImageW2 / TBI files:
Sector based - This means that data is copied from the exact location on the original disk to the new disk on a sector level.
Pros:
This means things like disk defrags are maintained when being copied.
You are getting a true exact copy of the original origin disk.
Handles multiple partitions very well.
Cons:
The size of the target disk must have atleast the same number of sectors or more (aka same size disk or larger) than the origin disk that the image was created on.
Typically requires an entire target disk to be formatted during deployment because the target sectors where the data will be placed could be any where on the disk. Full target disk data loss.
*Note: this can also be done at the partition level instead of the full disk, the same principles above apply - just replace disk with partition when you read it.
Microsoft's ImageX / WIM files:
File based - This means that data is copied to the next available space on the target disk - this is equivalent to you copying and pasting files, with built-in mechanisms to handle system flags, file permissions, etc.
Pros:
The size of the target disk only needs to be large enough to fit the size of the data in the WIM. This means that the origin disk may be larger than the target disk.
You may deploy the WIM over an existing file structure and it will merge the two. Any previous files of the same name(s) will be replaced, and the rest of the target disk's files will remain untouched.
You may re-image a target disk without having to back-up and restore user data. This means you must skip the format step, and typically add custom clean up commands to remove things like C:\Windows.
Cons:
Not a true exact copy of the original origin disk at a sector level.
Things like disk defrags are lost when deploying to target devices.
I typically use ImageW2 for my standard images because I want to know that I am getting an exact perfect copy of my image placed onto all new devices. Just make sure that you create your image on a smaller disk, I typically use a VM. However I use ImageX to do utility tasks like upgrading devices or backing up user data and restoring it to another device if necessary. ImageX does not have to use an entire disk, it can image just a folder if you want. This means you may take 4 different ImageX WIMs and deploy all 4 to the same device and have them all merge together to form one image. This of course has a higher learning curve as you start to get away from the simple "full image, sysprep, full deploy" methods, as well as many more unexpected results.
As for your second question - it does exactly that. When it finishes the sub-template it returns immediately to the main template. This works multiple layers deep as well.
Hope this helps,
Peter