I'm not feeling it.
I watched some of the anime version of Hataraki Man, and enjoyed it; it felt like a somewhat-heavy slice of life title, with plenty of josei angst to go around.
The manga just... is missing something. I know it came first, but I found it far more boring and uninteresting to read. Somehow the topic of workaholics (with a heavy dose of psychological conversation) doesn't make for a good read. It's hard to follow the character, hard to keep people straight (given there are so many names and faces to deal with), and overall pretty soulless.
That being said, the chapter involving Hiroko's boyfriend was melancholy and sad in a good way - you feel bad for his character for sure, even though up to that point you've only been exposed to Hiroko and her perspective.
Overall I'd avoid this one unless you really, really liked the anime and want to see its origins. Decent artwork and characters that you may come to love, but the progression and amount of boring dialogue sort of killed it for me.