I have made a few shrubs, and have been really happy with the results. Keep in mind that they tend to be quite sweet, and you usually only need a healthy splash to really influence the cocktail. Usually, a splash with your spirit of choice and some soda or tonic water is a quick and easy cocktail, with tons of variations possible.
I want to experiment a lot more, but so far the best ones I've made have been:
cucumber/lime: great with a gin or vodka + tonic.
Orange honey: Highly recommended as a substitute for simple syrup in an old fashioned.
Basil Peach: Fantastic with bourbon or rye.
Feel free to pass along any successful combinations you discover!