Microsoft DISM is rubbish

I've used this a few times and at first glance it seems like the mutts mahoonies. Microsoft have cracked it, awesome. It's built in to the O/S, it's powerful whats not to like. Quite a lot actually. Here are a list of my dislikes.

1.) It takes ages to unmount an image, even with discard. Surely this should take no time, there isn't anything to write to the image ?

2.) Shutting down a machine with a wim attached leaves stray stuff around that it's really difficult to delete. Even the cleanup-wim option seems confused.

3.) It somehow manages to screw up ntfs-3g in Linux. Nice. It's gotta be bad to mess up Linux.

Oh well.