Over the last few weeks, I've played with a number of popular performers in both the "Yeshivish music" and "Carlebach/J folk-rock" communities.
Both communities have their own conventions in terms of repertoire, chord changes,and aproach. For example, all of the J-folk rockers called "Oz V'hadar" and "Ivdu" (Diaspora) while all of the Yeshivish/Chassidish singers called "Ben Bag Bag" and "Zochreini Na". All of then J-rockers also play an instrument, usually guitar, while none of the "suits" do (although some of them do know a few guitar or piano chords and have been known to "play" on occasion.)
There are also some performance techniques I'm noticing. For example, almost all of the Yeshivish/Chassidish singers do the following:
1) Splice the low part of Zochreini Na with the high part of Hinei Ma Tov (MBD).
2) Slow down the tempo drastically on the C section of one of the Lubavitcher Nigunim and the B section of Ein Od Milvado going rather abruptly from freilach to disco and back. Incidentally, while the bochurim all start jumping up and down at this point, it totally kills the dancing on the women's side until the tempo picks up again.
3) End the last song by medleying the high part of "Someday" with the high parts of various Yerusholayim songs (slow and fast) like Carlebach and/or Shwekey version of "Im Eshkacheich", "Yerusholayim Ora Shel Olam", and the like (so long as they're in the same key).
4) They don't bring sheet music, even for the original songs off of their own albums. (There was one exception this go-round.)
The J-Rocker approach is the following:
1) They all play "Oz V'hadar" with a similar rock groove.
2) Play "Ivdu" in a heavier rock style than the original.
3) Choose Carlebach songs that have been recorded by the Moshav Band and Soulfarm. Particular favorites seem to be the tunes off of Moshav Band's album, "Return Again."
4) Dress down for the gig, no matter the venue.