Well the Decca CD of PIPPIN is much much better than the old Motown issue sound wise. Decca used the original mster tapes. Motown dubbed teh heavily compressed LP master. Decca also includes some interesting bonus tracks.
As a general rule the Decca Broadway reissues are almost always improvements sound-wise (but be careful that some - LITTLE SHOP OF HORRORS and BIG ROVER come to mind) are repackages of the original releases with the Decca Broadway emblem added to the sleeve. (These editions retain the original Geffen and MCA catalog numbers.)
The 5 "deluxe" editions that RCA put out in a last gasp before Sony took control are worth getting for the bonus material. While I do not like the cardboard packaging, the booklets do include updated notes. The remastering doesn't seem to be much of a jump over the originals but they sounded fine. The bonus material is interesting but you don't generally play it every time you play the disc.
HELLO DOLLY is essential because it includes Ether Merman's privately made recording of "her" two songs from the score (released as a 45--rpm single during the run of the show.) It also samples the Pearl Baily and Mary Martin albums and includes an interview with Carol Channing being her irresistibly scatterbrained self.
HOW TO SUCCEED... has bonus tracks: Walter Cronkite's narration and a couple of reprises from the revival (H2$), a few demos by Loesser and interviews with Robert Morse and Charles Nelson Reilly.
HAIR is a 2CD set, One disc is the Broadway cast (with all the additional material added for the first CD release) while the 2nd disc has the somewhat rarer off-Broadway cast recording so you can track the changes. (It isn't a very good recording however.) The 2nd disc is filled out with an interview with Galt MacDermot.
FIDDLER ON THE ROOF has the same bonus material from the first CD release and adds an interview with Sheldon Harnick plus segments from AN EVENING WITH SHELDON HARNICK in which he performs a couple of cut songs, and Vladimir Spivakov's violin rendition of "If I Were a Rich Man."
OLIVER adds some tracks from the original London cast album (including "That's Your Funeral" which was cut from teh Broadway version) and Patti Lupone singing "As Long As He Needs Me" which she sang in the (unrecorded) flop 1984 revival. (The track comes from her 1993 disc Patti Lupone - Live.) There is also an interview with Donald Pippin.
The recent eco-pack reissues from Masterworks Broadway are the original releases, not the deluxe editions.
You can easily go broke buying reissues, so the question is is it a score you like and listen to enough to warrant an upgrade? And is the bonus material something you can't live without? Or would borrowing a copy from the local library just to hear once suffice.
Cast albums are NOT "soundtracks."
Live theatre does not use a "soundtrack." If it did, it wouldn't be live theatre!
I host a weekly one-hour radio program featuring cast album selections as well as songs by cabaret, jazz and theatre artists. The program, FRONT ROW CENTRE is heard Sundays 9 to 10 am and also Saturdays from 8 to 9 am (eastern times) on www.proudfm.com