Are undergrad professors the be-all end-all for MS recommendation letters? I am applying to several MS programs in computer science. I graduated last year with a bachelor's in physics and a CS minor. So far, two of my recommenders are:


The professor I did research with in a physics lab for 2+ years as an undergrad
My current manager in a data science / software development role


I'm torn about who to use for the third letter, between my undergrad academic advisor (and current chair of the physics department at that institution) and a science journalist and producer of the radio show I worked on last summer. 

I think the journalist would have more interesting things to say about me but I keep reading about how committees want to see letters from professors. I had a good relationship with my academic advisor but he'd probably just repeat things that my research leader would say. Is position really more important than breadth in this case?
Request both. Then, use a combination of them tailored to what position you're applying for. An academic position may call for the academic-heavy reference list, whereas an industry position or a position where someone of influence is acquainted with one of your recommenders, would perhaps change that equation.