My experience: Peanut Butter Cup, Nootella, Fuzzy Tatas and Krunch Berries need steeping time to fully develop.
Strawberry Milkshake changes with steeping, good in both forms, really couldn't pick a better between them but it changes.
Strawberry Lemonade degenerates with steeping, mainly the tartness dwindles. Still good, just personally not as good, I love that tartness makes it truly taste like street corner Lemonade vs light Minute Maid (again I like both! but prefer the tartness, I say light minute maid because it doesn't taste like sugar + lemonade, just lemonade).
The rest ehh not as much change, perhaps more developed flavor and minor changes, but they don't stand out as needing to be given advance warning. They're just good.
Right now I have the Keylime Pie, Peach Cream, Raspberry Custard, Blueberry Custard, Mandarin Cream, Peanut Butter Cup, Wubbabubba, and Strawberry Milkshake going in my various mods using them as I desire a different flavor. Honey Milk used to be my favorite but they changed that recipe up some, still a great flavor but it's been beaten out by most of the above (not all, just I needed a wider variety of flavors, Honey Milk is a bit more basic, great but simple Still easily in top 10, but perhaps bumped out of top 5 at this point for my personal taste).