So tell me again why I would want a Supercardioid versus a Cardiod polar pattern. What good will the lobe be if I mostly record on stage?
What good does the lobe ever do?
Haven't used either of these mic lines personally, but can't resist playing the devils advocate. Here's a few potential good things about the rear lobe-
It makes X/Y a viable choice if you want to run an X/Y config (IMHO. I dislike X/Y with cards except for close mic'ing, yet using supercards can be work pretty well, somewhat like directional blumlein).
For similar reasons, it helps some other non-X/Y configs work correctly (thinking about configs not used around here much, specifically 3 channel OCT) by picking up a small amount of reverse polarity content at a reduced level from the opposite direction.
The traditional Senn supercard response is also interesting in that they chose a pattern where the off-axis sensitivity at +/- 90 degrees is the same as the sensitivity at 180 degress
(both are 6dB down from on-axis I believe) [edit- both are 10dB down]. I assume the newer 8050 is the same. John please correct me if I'm off on this.
So there are some specific reasons to desire the rear lobe, but as you are well aware, the primary reasons for choosing supercards over cardioids is not the rear lobe in itself, but their higher ratio of sensitivity to on-axis sound in comparison to all other combined directions; their conical rearward null pattern; and their generally reduced low frequency sensitivity at the distances we record, including on-stage.
All that said, cardioids are probably a better choice generally for most on-stage 2-channel configs.