I don't have the knowledge to technically critique a musical piece and saying: "Wow, this is a great mix! Keep up the good work!" feels a little trite, so I'll say something else.
Ben, this mix was stuck in my head all day long today. It's dark, eerie, yet somber atmosphere somehow hit close to home, and it slowly started to make me feel depressed. And even though I was kind of sad, I still couldn't stop thinking about it, nor did I want to stop. You could say, it was kiiling me, but I loved it (cookie to whoever gets the reference ). It stuck with me while driving to class, during midterms, lunch, study session, and it's in my head now. Most likely, I'll hear it in my sleep. And I can't think of a better compliment than that.
Now, if you'll excuse me, I'm gonna go download whatever I can find from this "Portishead", of which you speak.