Advantage in Lightroom is the dual display, virtually Original and edited picture next to each other, which does not offer ACDSee in the form: You have to click and you get the original display again, you have to let you back the edited version.
But it's probably exactly what makes the preview of ACDSee as fast.
Error in the software are me not noticed at all.
I use to 90% only the tools in the "developing" tools "Edit" I use only when I want to edit portions of the image.
All in all a very well thought-out and understandable even for the layman menu navigation and a very powerful image program!
Clear recommendation from me!
Greeting
Lieve-Jong