I was surprised I didn't like this, I guess I prefer my Manhattans sweet!

Perfect works great on both Manhattans and Rob Roys!

After reading an article on Perfect Manhattans possibilities on the Wine Enthusiast site, I tried this variation that I think is really terrific. I really liked the way the lemon + briny flavors worked with the rye and vermouths.
2 oz Rittenhouse Bonded Rye
1/2 oz Dolin Dry Vermouth
1/2 oz Carpano Antica Vermouth
2 dashes Angostura
Expressed lemon twist
Cocktail Onion (or green olive)

I used Rittenhouse Straight Rye. Great cocktail that has a really long finish. 5 stars.

Manhattan sweet too sweet
I'll take Manhattan is great for the cherry/complexity, but way to sweet
Manhattan Perfect: Just miss the cherry/complexity despite the garnish

So I combined them to make the best of all worlds:

2oz whiskey
1/2 Rosso Vermouth
1/4 Dry Vermouth
1/4 Cherry Brandy
2 dashes bitters

This gives it just a hint of cherry that plays nice with the garnish but the dry vermouth still keeps it balanced.

Interesting drink. I used to have my manhattan with 2oz bourbon (or rye for more character) 1oz sweet vermouth 2-3 dashes angustura 1-2 dashes fee brothers chocolate. This one is of course dryer but interesting in summer if you are looking for a "fresher" Manhattan

After a lot of experimentation (for Science), I've made this my go-to favorite Manhattan.