Simply put, Robbin's is probably the best text out there in the sense that it elaborates on mechanisms. Everything else seems to just be a summary of it, and I've noticed that when I've read some of the QBank explanations. I can tell they've just gone to Robbin's because sometimes much of what's written sounds a little too familiar.
The only problem is that it is not remotely designed for USMLE prep, so one should be selective when reading it. You don't need to read the minuscule details about all of the different sub-types of gastrointestinal malignancies, but it's solid if you want to know how asthma or pneumothoraces work, for example.
With respect to this thread, I'm already off on a tangent, but I can say that I personally have not used RR Path extensively for my prep. I only bought the book because I was curious based on its great reviews. If you're at the beginning of MS2, I would suggest going through it (or Robbin's), alongside BRS Path, but absolutely don't touch it within the designated boards prep time.
