I always look at RS spoiler rate like I look at my grades. I take how many times he has stuff right compared to how many times he posted spoiler info. If his rate is a high enough percentage, he earns a good grade. To me, he would be sitting with an A right now and you can't really do much better than that.
However, he did make the mistake last season of not sticking to his guns. He had stated that Chris was F2 but he didn't know what happened to Roberto. But he was pressed and decided to go with saying Ali picked no one. He had the same dilemma with the ending of Jillian's season but never put an affirmative ending out there on that season until we all knew from the ATFR was taped. I think he learned from last season to post what he knows for sure. That's one of the reasons I think he is right this season. I don't think he would risk being wrong, his ego is much too big to handle not putting the info he has out there.
With all that said, I don't make my decision about who the F1 simply because RS says so. Most times, I try to prove him wrong. However when I do that, I often discover proof to solidify his spoilers. For me, RS is a piece of the puzzle, not the whole thing.