I agree with Natalia that testing would be useful here. However, I feel like there's still a rule of thumb for your question. The main factor to consider here: What are you (is your company) aiming to achieve? You want to get potential users engaged in the website, which preferably leads them to using/buying your product.
With productivity software, this is difficult to achieve with screenshots since its purpose is to make a given work task more efficient (quicker, easier, more convenient etc.). The usage of colors and images is much less frequent than in fun and engaging B2C software.
Therefore, it might be adviseable to convey this message ("we make your work easier") with an illustration instead of actual screenshots.
(Note, that this is only true for the landing page, to shape a first impression, because First impressions matter. When it comes to feature descriptions, documentation, etc. real screenshots are invaluable)