Progress Bars I Have Loved:
* Tells people what stage we're on. "Downloading", "Installing", "Cleaning Up".
* Can make bar for each step or guesstimated across all steps, either is ok.
* Do not show sub-step time estimates. If you show time estimates at all, do it for the whole process.
* Bar represents definite knowable progress: files moved, MB downloaded, etc. It thus never moves backward. If the stage has nothing knowable, make the bar full-width and stripey as a spinner equivalent.
* Able to open a verbose view that shows log stuff: actual numbers and filenames. The MacOS installer has this and good lord it was important when the MacTeX bug hit
Does this surface information that unempowered users don't need? Sure. Their eyes will just glaze over and it'll be fine.