The BYU fan eye test. You guys love Tonga because he's your guy. He's a good BYU DT. That's it. Utah's top 3 or 4 (Fotu, Penisini, Tonga, Moala) are as good or better.

But I do agree that he's your best DL. In fact, he's significantly better than any other BYU DL, which is why he's going to get double-teamed a lot.

If you want the stats, I can help. Remember that BYU faced the #69 schedule in the country last year while Utah faced the #26 (per Sagarin):

Utah's Fotu: 34 tackles, 7 TFL, 3.5 sacks
Utah's Penisini: 38 tackles, 7 TFL, 2 sacks
Utah's Tonga: 12 tackles, 3 TFL, 2.5 sacks, 1 INT
BYU's Tonga: 30 tackles, 4.5 TFL, 2 sacks

Tonga's good. Solid. Not spectacular.