This afternoon, I was having some trouble with an HSQC (Heteronuclear Single Quantum Coherence Spectroscopy) spectrum I was trying to acquire, and the spectroscopist recommended I try HMQC (Heteronuclear Multiple Quantum Coherence) spectra, as they are more robust. I did so and got a very nice spectrum in about half the time an equivalent HSQC would have taken, and didn't have to phase it, to boot.
So, what is the downside? Why doesn't everyone use HMQC spectra instead of HSQC? I know they are rather different on a quantum-mechanical level, but as an end-user what, if any, is the difference in the data the two techniques give me, what are the advantages and disadvantages of each, and in what situations might I prefer one over the other?