I don't know what's best. DFEI and S&P+ defense both seem to be really good in getting the noise and gunk out (garbage time, downplaying weak opponents, …).
S&P+ had us as the #66 defense last year and DFEI had us as the #63 defense last year. I'm not going to beat myself up over the difference between 63 and 66. They're both middle of the pack, your defense won't be the thing that gets you to a bowl game numbers.
In DFEI (lower is better), we had a rating of 2.25 (#63) and went 4-6. Stanford had a DFEI of 2.24 (#62) and went 9-5. Michigan State had a DFEI of 1.64 (#25). Clemson was #1 at 0.83, UGA was #5 at 0.98, and VT and Miami were both top 15.
I made a chart. When you get around the top 10 or so, defenses don't gradually separate from the pack, they dramatically do. Same thing for the bottom 10 defenses. Between that, it's gradual improvements:
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S&P+ is the same thing, just a little smoother. We're right in the middle on both. Not awful, but textbook mediocre:
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