I own the R1 CE, owned the R3 before that and have sampled the R2 CE (bought it for a friend without cc). From memory, I'd say the R3 (which actually is R0, IIRC) is the sharpest but suffers a bit from aliasing, and the R2 and R1 transfers are identical aside from inherent PAL-NTSC differences.
BTW, the R2/UK version is edited (very) slightly: the shot of the needle entering John Travolta's arm was reframed at the 'request' of the BBFC...
It seems like R4 was never issued with non-anamorphic. But its menu has no animation and very poor in presentation. Bright day light scenes are quiet sharp but details in dark areas are weak.
Do you think R4 SE's anamorphic is same as R1 CE's? Because I don't want to double-dip an identically transferred DVD.