first and foremost is the packaging. iba ang dating ng r1. although there are some r3 releases that are better than their r1 counterparts, mas marami pa rin ang better looking r1 releases. case in point, look at the bttf trilogy. the r1 version comes with a holofoil slipcase unlike the r3 release na ang pangit ng dating although it has a dts track unlike its r1 counterpart. the king kong release also comes to mind.
to sum it up, some r1 dvds (or r2 for that matter) are classier looking than some of it's r3 counterparts.(unless it's a warner release. just look at c interactive dvds and you're better off...)