I love vermouths and quinquinas, and find that they make so much more of a difference in the character of cocktails than the spirits we fuss over so much. Of all that I've tried, these are my 'house' stable of vermouths:
Dolin is my winner for dry vermouth -- I think it is perfect. Vya is also good, but a little too vegetal and bitter for my taste. Their Whisper Dry is also excellent, but double the price of their standard -- which is not better than Dolin, to me. Cocchi Americano is the best all-around quinquina that I have tried yet, even more than Kina l'Avion D'Or, though I will try it out again. Recently found some Saliers but have not yet had the pleasure of trying it. Lillet (both red and white) are musts for me -- they make everything good. And the Dolin Blanc is perfect. M&R's blanc reeks of chocolate to my palate.
Sweet Vermouths! Ah, As much as I enjoy Carpano Antica and Vya Sweet, the Cocchi Torino takes the cake for me, and is my go-to for Manhattans and Boulevardiers. I have not been able to find a better Negroni vermouth than M&R though -- it is a perfect blend of winey and earthy notes. And then there is the Dolin for most other gin-based cocktails, where its fruity and winey notes are well-displayed.