The original recording with Robert Morse is all right - marred by distortion (that also mars many RCA recordings of that time - they had the mic levels way too high.) There is better sound on the 1995 revival cast (Broderick) and it is the most complete recording to date (missing "Cinderella Darling" which was cut from the revival.) IT also includes some of the book passages s recorded for the production by Walter Cronkite. Broderick is fine but Megan Mullally is a shrill Rosemary - no warmth in her voice at all.
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