For me, it was perhaps simple-scan, a very simple and efficient GUI to scan documents. I used it with my Brother printer / scanner and it works like a charm. Especially since I do not scan stuff often, so a program with more complex UI would have the effect that I forget how to use it until the next time.
Reaper is nifty, but it’s not FOSS, which would be the only reason why I’d give up Bitwig. (I know that’s not what the thread asked, but that’s my reason for not using Reaper.)