First, full disclosure: I am a big fan of Lora Cecere so understand I almost always think what she says is big news - I have been following her since her AMR days. Now, having said that, she posted an extremely interesting blog post entitled "Don't Perpetuate The Hoax of The Gartner 25" that is well worth reading.
In fact, I will summarize but clearly you need to go to the post to read the entire entry.
Back when this started, I was actually on the board that voted (AMR days) and I always thought it was moving towards what Lora calls a "beauty" contest and now I believe it is fully just that. Most of it is about brand name recognition. After all, how could a company that so misses demand projections that their new products are unavailable be in the top 25 (Apple) unless it was just brand recognition.
I agree with Lora, to really rate supply chains you have to look at the detailed figures and facts and let the data speak. As she cites in the post, performance + real improvement (in a measurable way), is what should drive the top supply chains.
Go to her blog and give it a read for yourself!