1970 vs 1971 Dart bumper, which looks better?

dustoff440 said
Draw back not seen as easily as 71-2

No, the single '70 Dart tail/brake lights give higher objective performance than the '71-'73 items (unless you modify the '71-'73 Dart setup like this, which winds you up with better overall safety performance than either stock system unmodified).

Remedy, aftermarket extra bright LED bulbs.

No, those don't work; in fact they reduce the performance of the brake/tail lamps to unsafe levels. See here.