All the BAK Revolver X2 & X4, and the TruXedo Sentry & Sentry CT tonneau covers use aluminum slatting and have a vinyl material on top to make it look classy.
Quality wise, all 4 tonneaus are very equivalent. The Sentry CT has a more durable fabric than the Sentry which is better for more rugged usage.
The differences are mainly cosmetic. The BAK Revolver's have silver aluminum slatting whereas the Sentry's have black aluminum slatting.
Between the Revolver's, the X2 is a standard black whereas the X4 is matte black.
The prices are all similar, with the higher end version of each brand costing slightly more.
For an easy-to-read comparison, please see our chart below.