It really comes down to what you prefer. If you can read (quickly) and, more importantly,
retain what's in Big Robbins, go for it. The few sections I've read in Big Robbins, I've forgotten pretty quickly, except for the main concepts (and you can get that same "big picture" understanding from something less dense/less time-consuming than Robbins). I've heard of people doing really well on Step 1 using Robbins throughout M2 year and I've heard of people doing really well on Step 1 without ever touching Robbins.
Personally, I'm a slow reader. If I read through Big Robbins for everything, I'll only have time to go through it once or twice. At most. With such few passes over the material, I wouldn't retain the information for the long-term (which I've already mentioned regarding the few sections I've read). This is my strategy:
Pathoma + RR + Robbins Question Bank + WebPath + USMLERx + UWorld (just starting this now)
With that combination, there's really no point in reading Big Robbins for me. I have not noticed any difference in knowledge-base or performance between myself and those in my class who do take the time to read Big Robbins.
There are many different approaches to being successful in med school. Just do whatever works for you.