Performance-based metrics like NET, KPI, BPI, and Torvik are a better indicator of how good a team is, while results-based metrics like WAB and SOR are a better indicator of what a team has accomplished in the season.
The committee uses both metrics to determine what teams get in and where to place them in the bracket.
For example, Wisconsin has a Torvik rating that places them 22nd in the country (6 seed), but a WAB rating that places them 4th (1 seed). Averaging the metrics puts them at about a 4 seed.
Gonzaga is kind of the opposite, a Torvik rating of 1st (1 seed) and a WAB of 13th (4 seed). I'd expect them to still be a 1 seed, but if they do slip up at all and some of the major conference teams can dominate their conferences (Auburn, Baylor/Kansas, Purdue, Arizona/UCLA, ILLINOIS), they could slip despite being the overall best team. Even now they're probably not the #1 overall seed (I'd give Auburn that nod).