The biggest isssue have seen is that there is no way to stop a BUILD/ UPDATE from downloading. I mean there should be an option to pause but it downloads any way. I tried setting up my connection as Metered and this didn't help either.
For that reasons i pulled out of Insider program and now i have been facing issues with Cumulative update failed every time.
The issue is getting serious as it forces me every time to "Update and Shutdown", "Update and Restart" and the whole cycle of installation and then undoing changes goes on and on.