Blimey, it flies off the shelves in our local pharmacy at this time of year - can just imagine locals' reactions to a pharmacist lecturing them on the Badness of Medised
We hardly ever used it for dd1, just heavy heavy colds, but dd2 has a floppy larynx and narrow airway, which clogs easily with snot, and has had endless choky snotty colds this winter. She wakes up every time, she gets very upset, its very scary to hear, and none of us get any sleep: so I shamelessly admit to using it, at night only, on many occasions between September and December - and it makes all the difference, in her case.
Along with a humidifier, Karvol, raised bed head, reflux meds, and lots of rocking and cuddling.
Also, rarely, use it myself when very very coldy, on basis that it has no alcohol in it and thus better for me (can't take alcohol) than grownup equivalents.
Honestly, used appropriately, I think its a godsend.