I have all of them and love them probably a bit disproportionately to some of my other pieces of gear, haha. They all just have such nice sonic character and (to me) are classic but still quite unique. I’m sort of in the same boat about the Biscuit—I do enjoy its sound quite a bit but have used it the least. I’ve been very tempted to sell it due to what I could get for it, but similarly fear never being able to own one again. Who knows, maybe I’ll cave.
Boum is very versatile, but ironically one of its features I use most is just simple boost. I find it does an excellent job of brining out the character of a synth going into my interface. My Model D, Juno, and SH-101 really sound a lot richer and, for lack of a better word, more “awake” after passing through the Boum. Regardless of what you end up using yours for, I’m sure you’ll enjoy it. Good purchase!