I used to absolutely love both Espresso and CSSEdit too but I've now switched to a more minimal editor. I started using LESS so CSSEdit wasn't cutting it anymore. Instead I use either Less.app or CodeKit which monitors your working directory, automatically compiles LESS to CSS on save, and refreshes the browser tab of the site you're working on.
I do agree that rolling CSSEdt into Espresso isn't the same. I don't know why but I liked CSSEdit better when it was a standalone app. Anyway, as an alternative to CSSEdit or the other desktop apps that give you the instant refresh, you could always write a shell script that watches your working directory and executes the LESS (or SASS/SCSS) compiler then refreshes your browser. I actually used that once but lost it while formatting the laptop it was on. The part that watches the folder and executes the compiler is easy but I had someone else help me with the browser refreshing part.
I do agree that rolling CSSEdt into Espresso isn't the same. I don't know why but I liked CSSEdit better when it was a standalone app. Anyway, as an alternative to CSSEdit or the other desktop apps that give you the instant refresh, you could always write a shell script that watches your working directory and executes the LESS (or SASS/SCSS) compiler then refreshes your browser. I actually used that once but lost it while formatting the laptop it was on. The part that watches the folder and executes the compiler is easy but I had someone else help me with the browser refreshing part.