Zeroscope seems a very handy 1u-tool to me 
Aesthetics too important? I don’t know. The nice thing about modular in general and Eurorack particularly is that it is “easy” to make a very personal (or personalized) music instrument (or weird scientist laboratory
). I think aesthetics is (or makes?) a part of that “personal bond”.
I use a O’Tool+. A present from my spouse. She was really liking the DATA on all the youtube movies. It helped her to understand what certain modules do. I chose the O’Tool+ because of aesthetics, size and costs. I use spectrum analysis on it, but only in combination with my Morpheus. Very helpful with that module. When I`m jamming I sometimes use my (t)rusty old TEAC EQA-20. More as visual aid then an in depth production tool.
I just read your biography. Nice.
So “Dutchmaster”? I’m from the Netherlands
If you want to hear some jazzy dutch spoken word, check this…