This series is good if you already have a sufficient working knowledge of pathology to form a reasonable differential, and can then narrow it down to the right diagnoses.
A great at the scope reference guide.
Bought it back in the day but maybe only used it twice for anything useful.
I read Rosai cover to cover as a second-year resident. Other than maybe being made aware of the different entities that can occur in each organ system, I didn't really learn a whole lot that I didn't already know from routine sign-out with the attendings. But Rosai certainly reads better than Sternberg. If you find reading stereo instructions fulfilling, then you're going to love Sternberg. I bought it back in 2009, have only opened it about 5 times, and now basically sits on my shelf collecting dust. I'll probably be donating it to the Goodwill or some other thrift store shortly because it's just taking up space and I know I'm never going to use it.
Also, as you advance in your training, the Biopsy Interpretation series and "A pattern-based approach" atlases by Lippencott and the "practical pathology" series by Elsevier are worthwhile. I use those routinely in my daily practice.
Edit: Also forgot to mention that as an attending, I absolutely find the AFIP fascicles to be well written and they're in their 5th edition with online access. As a fellow or attending, I would endorse having the set.